Awakening process of the electrical network in a vehicle with an electric drive train

Abstract

The invention relates to a device for activating a control unit in a second power grid from a first power grid in a vehicle with an electrified drive train, wherein the first power grid is electrically isolated from the second power grid and comprises: a signal generating module for generating a wake-up signal in the first power grid; a transformer, which is configured to transmit the wake-up signal and electrical energy from a first transformer winding on the first power grid side to a second transformer winding on the second power grid side; a rectifier circuit in the second power grid, which is connected to the second transformer winding and is configured to rectify the transmitted wake-up signal; and a switching element in the second power grid, which is connected to the rectifier circuit and is configured to activate the control unit (60) when the rectified wake-up signal is applied or not applied to an input of the switching element (50).

Description

Technical Field

[0001] The invention relates to an arrangement for activating a control unit in a second electrical network electrically isolated from a first electrical network, a corresponding method and a computing unit for carrying out the same. Background Art

[0002] Hybrid and electric vehicles typically use at least two power networks: a high-voltage power network or traction power network connected to the corresponding high-voltage battery, and a low-voltage onboard power network, also connected to the corresponding low-voltage battery. The voltage of the high-voltage power network can be, for example, 48V or 60V or even higher, while the low-voltage power network is typically supplied with a 12V supply. The two power networks are preferably electrically isolated from one another and are therefore potential-free relative to one another (particularly at higher voltages).

[0003] When the vehicle is turned off, the quiescent current consumption of the electrical loads should be minimized to prevent discharge of the low-voltage battery. Thus, the quiescent current consumption of the controller should not exceed approximately 100 μA, for example.

[0004] The high-voltage network can be selectively disconnected. When the voltage of the high-voltage network is switched on, or as soon as the minimum voltage in the high-voltage network is exceeded, this information is used to wake up a controller (which is connected to both the high-voltage and low-voltage networks) in order to ensure, for example, protective and safety functions. This potential-free transmission of signals is typically performed using inductive or capacitive signal transmitters, which typically require a voltage supply on both the primary and secondary sides. Therefore, the voltage supply for such signal transmitters must not be disconnected even when the controller is switched off, making increased quiescent current consumption (typically more than 100 μA) unavoidable. Similarly, when using optical signal transmitters, at least one pull-up resistor between the phototransistor and the battery is required, which also undesirably increases the quiescent current consumption. Summary of the Invention

[0005] According to the present invention, a device and a method for activating a control unit in a first electrical network electrically isolated from the second electrical network, as well as a computing unit for executing the activation are proposed.

[0006] The present invention utilizes the measure that the wake-up signal and the electrical energy are transmitted from a first electrical network to a second electrical network by means of a transformer, where they are used to control a switching element for activating a control unit.

[0007] This wake-up circuit enables the second network (e.g., a low-voltage onboard power supply in a vehicle) to be activated when the first network is switched on, without undesirably increasing the quiescent current consumption on the second network side. The energy required for wake-up or activation is transmitted via the transformer. In particular, the secondary side of the transformer and the rectifier do not include an external energy supply. In particular, the switching elements on the secondary side include semiconductor switches, and the rectified wake-up signal is applied to the switching terminals (e.g., gates) of the semiconductor switches. In this case, the energy for actuating the semiconductor switches (e.g., for charging or recharging the gates) originates from the primary side.

[0008] It should be emphasized that, depending on the concrete circuit implementation, activation of the control unit can be triggered both by transmitting or applying the wake-up signal and by disconnecting or canceling the wake-up signal.

[0009] According to one embodiment, the rectifier circuit may include a voltage multiplier circuit, so that the rectified signal reaches a sufficiently high level for the switching element.

[0010] The transformer windings at the potential barrier can preferably be designed as air coils. Alternatively, they can also be provided with flux concentrators or can accommodate such devices.

[0011] For example, it is proposed that the transformer be configured as a planar transformer. In particular, it is possible to configure the first and second transformer windings as lines on or in at least one printed circuit board, i.e., as windings that are either introduced into the printed circuit board or directly configured on the printed circuit board as parallel lines, for example, arranged in the shape of a long spiral. This embodiment requires only simple components and can be manufactured very space-savingly and cost-effectively, especially if the windings are distributed, for example, over several or all of the usable inner layers of the printed circuit board.

[0012] The signal generation module can generate a clock signal or a single signal pulse with a preset frequency as a wake-up signal. Here, an existing microcontroller, for example, can be used in a simple manner for this task.

[0013] According to one embodiment, the first electrical network is the vehicle's high-voltage network and the second electrical network is the vehicle's low-voltage network. This eliminates the need for a voltage supply on the low-voltage network side, so that the quiescent current at the positive battery pole (clamp 30 ) of the onboard power supply battery does not increase.

[0014] According to one embodiment, the wake-up signal can be generated based on the resonant frequency of an oscillating circuit formed by the first transformer winding and a parallel-connected capacitor of the circuit. In this way, the efficiency of the energy transmission can be significantly increased.

[0015] In this case, the wake-up signal can include a signal with a predefined frequency or also individual signal pulses.

[0016] A computing system according to the invention (eg, a control unit of a vehicle) is configured, in particular in a programming manner, to execute the method according to the invention. Such a computing system is connected to two power grids and has a device according to the invention for activation.

[0017] Further advantages and configurations of the invention are apparent from the description and the accompanying drawings.

[0018] The invention is schematically illustrated on the basis of exemplary embodiments in the drawings and is explained below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 An exemplary circuit diagram showing a wake-up circuit according to the present invention; and

[0020] Figure 2 Exemplary method steps according to an embodiment of the present invention are shown. DETAILED DESCRIPTION

[0021] exist Figure 1 The circuit schematically shown in FIG shows components of a device for activation (wake-up circuit) that can be used in a vehicle with two separate electrical onboard power systems 2 and 4. In this case, embodiments of the present invention can be used in any vehicle with an electrified drive system, for example in plug-in hybrid vehicles (PHEVs), full hybrid vehicles, pure electric vehicles, etc. The two onboard power systems are usually described as a high-voltage network 2 and a low-voltage network 4, which have their own energy supply, for example by connecting batteries (not shown) separately. In this case, the low-voltage network 4 can be, for example, a 12V onboard voltage network, while the high-voltage network 2 can have a battery voltage of more than 60V, wherein the network voltages given should only be used as examples and are not important for the present invention.

[0022] In order not to increase the quiescent current consumption, according to the present invention, the wake-up signal is transmitted from the high-voltage network 2 to the low-voltage network 4 via a transformer 30, which can transmit both the wake-up signal and the power or energy (which is used to supply the switching elements for waking up the high-voltage network 2) from one network to the other between its two windings 32, 34, without requiring a separate current supply on the low-voltage network 4 side.

[0023] Figure 1 The vehicle's high-voltage network 2 is shown on the left, while the vehicle's low-voltage network 4 is shown on the right. The two networks are electrically isolated from one another; the dashed line between the two coupled coils indicates potential isolation 70. The primary-side coil 32 on the high-voltage side 2 and the secondary-side coil 34 on the low-voltage side 4 together form the transformer 30.

[0024] The module 10 for signal generation is located on the high-voltage side 2 , and the module can be, for example, a corresponding microcontroller or a module connected to the supply voltage V dd1 The signal generating module 10 can be, for example, a frequency generator in the form of a microcontroller that already exists for other purposes. Alternatively, instead of generating a clock signal with a predetermined frequency, a single pulse can be provided as the wake-up signal.

[0025] The generated wake-up signal is conducted to the optional coil driver module 20, which is also connected to the supply voltage V dd2 and ground potential, wherein the coil driver supply voltage V dd2 and the clock generation module supply voltage V dd1 Can be the same or different.

[0026] Furthermore, the primary-side coil 32 of the transformer 30 (i.e., the coil on the high-voltage network side) can form an oscillating circuit together with the parallel-connected capacitance of the circuit. Taking the resonant frequency of this system into account when generating the wake-up signal can significantly increase the efficiency of this circuit.

[0027] The wake-up signal can be transmitted to the primary-side winding 32 of the transformer, which transmits the signal to the secondary-side winding 34. This secondary winding 34 on the low-voltage network side can be connected to a rectifier module 40, for example, according to the principle of a multiplier-rectifier circuit or another voltage multiplier circuit (i.e., a circuit that generates a DC voltage greater than the peak value of the input voltage from an applied AC voltage). Rectifier 40 can thus generate a sufficiently high voltage level from the wake-up signal transmitted via transformer 30, which in turn serves as a direct input signal for switching element 50, which can be switched on, for example, by controller 60, based on this input (e.g., a voltage supply derived from low-voltage network 4). For example, an integrated circuit or a prefabricated chip, such as a system basis chip (SBC), which can provide the necessary voltage supply for the controller to be switched on, can be used as switching element 50. However, it is important that the rectified output signal is used solely as a switching signal for the switching element 50, for example, to charge or recharge the gate capacitance of a semiconductor switch (such as a MOSFET or IGBT) for switching on and off. The circuit section consisting of the rectifier 40 and the transformer 30 can thus be loaded without an external energy supply until the rectified output signal alone can switch the switching element 50.

[0028] According to an exemplary embodiment, transformer 30 for transmitting the wake-up signal is constructed with an air coil (i.e., a coreless winding). In a particularly advantageous variant, transformer 30 can be designed as a planar transformer, whose windings are arranged on a circuit board or printed circuit board. In a simple manner, windings 32, 34 can be directly wired on both surfaces of the printed circuit board, so that the base body of the printed circuit board forms the potential isolation 70.

[0029] The printed circuit board area required for such a transformer 30 can be further optimized by distributing the necessary windings 32, 34 of the transformer over several or all of the available inner layers, thereby utilizing areas of the potential barrier that cannot be used due to air gaps and creepage distances. This allows the wake-up circuit to be implemented with less space and cost.

[0030] Even though a coreless transformer is selected in this example, such a transformer can alternatively be replaced by an equippable transformer.

[0031] Figure 2 An exemplary method flow according to the present invention is schematically shown.

[0032] Here, in step 100 , a predetermined condition is met, for example, a high voltage of 60 V or more that is certain to trigger the wake-up process is applied to the first network.

[0033] In step 110 , a wake-up signal having a certain frequency is generated by a signal generating module (eg, a frequency generator), which is transmitted in step 120 from a first winding to a second winding of a transformer on the high-voltage side.

[0034] Step 130 indicates that a level is generated in the rectifier module by the transmitted wake-up signal, wherein the level thus generated is supplied to the input of the switching element according to step 140 .

[0035] In step 150 , as a result of the input level applied at the switching element, the necessary supply voltage for the controller is provided via the switching element, so that the controller can be successfully woken up or activated.

[0036] It is also possible that the switching element or the system basic chip on the low-voltage side is configured so that it can switch on or off different supply voltages in response to different signals (e.g., high-voltage wake-up signal, CAN wake-up, positive signal of the ignition start switch at clamp 15, etc.).

[0037] In an alternative embodiment, the wake-up signal can be implemented in such a way that the wake-up signal is permanently transmitted from the high-voltage side to the low-voltage side via the winding of the transformer, so that a high level is ultimately applied to the switching element and a low level is obtained by at least temporarily disconnecting the wake-up signal, thereby triggering the wake-up process.

Claims

1. A device for activating a control unit (60) in a second power grid (4) from a first power grid (2) in a vehicle with an electrified drive train, wherein: The first power grid (2) is electrically isolated from the second power grid (4), and comprises: a signal generating module (10) for generating a wake-up signal in the first power grid; A transformer (30) is provided for transmitting the wake-up signal and the electrical energy from a first transformer winding (32) on the first grid (2) side to a second transformer winding (34) on the second grid (4) side, a rectifier circuit (40) in the second power grid (4), the rectifier circuit being connected to the second transformer winding (34) and being configured to rectify the transmitted wake-up signal, and A switching element (50) in the second power network is connected to the rectifier circuit (40) and is configured to activate the control unit (60) when a rectified wake-up signal is or is not applied to an input of the switching element (50).

2. The device according to claim 1, wherein The rectifier circuit (40) includes a voltage multiplier circuit.

3. The device according to claim 1 or 2, wherein: The first transformer winding (32) and the second transformer winding (34) are designed as air coils.

4. The device according to claim 1 or 2, wherein: The transformer (30) is designed as a planar transformer.

5. The device according to claim 4, wherein The first transformer winding (32) and the second transformer winding (34) are configured as lines on or in at least one printed circuit board.

6. The device according to claim 1 or 2, wherein: The signal generating module (10) generates a clock signal with a preset frequency or a single signal pulse.

7. The device according to claim 1 or 2, wherein: The first electrical network (2) is a high-voltage network of the vehicle, and the second electrical network (4) is a low-voltage network of the vehicle.

8. The device according to claim 1 or 2, wherein: The switching element (50) has a semiconductor switch, and the rectified wake-up signal is applied to a switching connection of the semiconductor switch.

9. Method for activating a control unit in a second electrical network via a first electrical network in a vehicle having an electrified drive train, wherein: The power grids are electrically isolated from each other and comprise: generating a wake-up signal in a signal generating module in the first power grid, transmitting the wake-up signal and the electric energy from a first transformer winding in the first power grid to a second transformer winding in the second power grid through a transformer, rectifying the transmitted signal by a rectifier module in the second power grid, and The rectified wake-up signal is supplied to an input of a switching element (50) in the second power supply network, wherein the switching element is configured to activate a connected control unit (60) in response to the application or non-application of the rectified wake-up signal.

10. The method according to claim 9, comprising generating the wake-up signal based on a resonant frequency of an oscillating circuit, the oscillating circuit being formed by the first transformer winding (32) and a parallel capacitance of a circuit.

11. The method according to claim 9 or 10, wherein: The wake-up signal includes a clock signal with a preset frequency.

12. The method according to claim 9 or 10, wherein: The wake-up signal includes a signal having a single signal pulse. 13 . A computer unit configured to carry out all method steps of the method according to claim 9 .

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