Engine control unit

Abstract

The invention relates to a method (100) for reducing the energy consumption of an engine control unit (1), wherein the engine control unit (1) has an output stage (10), a control unit (30), a first supply line (40), a second supply line (42) and a central switching element (60), wherein the output stage (10) comprises at least two half-bridges (H1, H2, H3), each with a connection point (11, 12, 13) between a low-side switching element (T2, T4, T6) and a high-side switching element (T1, T3, T5), and wherein the control unit (30) is designed to control the low-side switching elements (T2, T4, T6) and high-side switching elements (T1, T3, T5), and wherein the supply lines (40, 42) supply the output stage (10) and the control unit (30) with energy, and wherein the central switching element (60) is formed in the first supply line (40) or the second supply line (42), comprising the steps: • Blocking (110) the high-side switching elements (T1, T3, T5) and switching (120) the low-side switching elements (T2, T4, T6), or Blocking (110) the low-side switching elements (T2, T4, T6) and switching (120) the high-side switching elements (T1, T3, T5); • Reducing (130) the current through the central switching element (60) such that the low-side or high-side switching elements can be switched and / or blocked.

Description

The invention relates to a motor control unit for controlling an electric motor and to a method for reducing the energy consumption of a motor control unit.Prior ArtMotor control units for controlling an electric motor are known. The electric motors drive, for example, a windshield wiper of a vehicle. If the windshield wipers are not required (standby) despite operation of the vehicle, they assume a parking position. The windscreen wiper is in standby operation. It is known to fully energize the motor control unit in standby, so that the windshield wiper is held in the parking position. The known actuation methods result in that, despite standby operation, the motor control unit is consumed in power as during operation or only slightly below it. In particular, there is a power consumption of 130 mA or more.Disclosure of the InventionThe object of the invention is to provide a method and / or an engine control unit which allows a reduction in the power consumption.The invention relates to a motor control unit for controlling an electric motor. The motor control unit advantageously comprises an output stage, a control unit, a first and a second supply line and a central switching element ( 60).It is advantageous that the output stage has at least two half bridges. According to one refinement, three half bridges are formed. Three half bridges allow driving of a three-phase electrically commutated electric motor. Preferably, each half bridge comprises at least one low-side switching element and at least one high-side switching element. A connection point is formed between the low-side and the high-side switching elements of each half bridge. The electric motor is preferably controlled via the connection points.The motor control unit advantageously has a control unit. The control unit is designed to control the low-side and high-side switching elements.It is also advantageous that the motor control unit has a first and a second supply line for supplying the output stage and the control unit with energy / current. The first and the second supply line are preferably connected to an energy source, in particular a battery.Furthermore, it is to be regarded as advantageous that a central switching element is formed. The central switching element is formed in the first or second supply line. The central switching element is preferably arranged in such a way that the current, in particular the current flow, preferably the current intensity, to the output stage and the control unit can be controlled by means of the central switching element. The central switching element is preferably arranged upstream of the output stage and the control unit, in particular one of the supply connections of the control unit.The central switching element is preferably controlled by means of the control unit itself. The control unit can thus actuate the central switching element in such a way that the central control element only allows the current actually required, in particular for the basic operation of the control unit. This results in an advantageous current reduction in standby operation.It is advantageous that the electric motor is used to drive a wiper system, in particular a front wiper system. The electric motor can also be used in a pump, a fan or an actuator driven by an electric motor, in particular a steering drive, a seat driveThe measures listed in the dependent claims result in advantageous refinements and improvements of the features specified in the main claim.An advantageous further development is characterized in that a further control unit is formed, which provides a PWM signal in particular to the control unit. The further control unit communicates in particular with the control unit whether and / or how the electric motor is to be actuated or whether the motor control unit is in standby operation. In particular, the control unit is designed and configured to actuate the central switching element and / or the output stage as a function of the PWM signal provided.In particular, "provided" is understood to mean that the PWM signal is generated and / or transmitted, preferably transmitted.An advantageous development is that a further control unit is formed, which has a communication interface. The communication interface allows communication with further control units, in particular an engine control unit or a central control unit, of the vehicle.The invention further relates to a method for reducing the energy of an engine control unit, in particular in standby operation.The motor control unit advantageously comprises an output stage, a control unit, a first and a second supply line and a central switching element, as already explained above.The output stage comprises at least two, in particular three, half bridges. Each half bridge comprises at least one low-side switching element and at least one high-side switching element. A connection point is formed between the low-side and the high-side switching elements of a half bridge. The connection point serves in particular for establishing a connection with the electric motor. The control unit is designed and configured to control the low-side and high-side switching elements. The activation is effected in particular by applying and / or changing a voltage to the switching element. The first and the second supply line supply the output stage and the output stage control unit with energy. Preferably, the first and second supply lines electrically connect to a power source. The central switching element is formed in the first or second supply line. The central switching element permits switching or blocking of the energy supply to the output stage and the control unit.The method comprises the steps listed below:In one method step, the blocking of the high-side switching elements and the switching of the low-side switching elements take place. Alternatively, the blocking of the low-side switching elements and the switching of the high-side switching elements take place. As a result, no current flow takes place from the energy source through the final stage. At the same time, the switching brings about a self-locking of the electric motor.Switching is understood here to mean that the switching element is controlled in such a way that it is conductive, preferably allows the current to flow, in particular a current flow. Preferably, the current intensity is changed by means of the switching.The blocking can take place, in particular, passively or actively. In passive blocking, no voltage is applied to the switching input of a switching element, in particular the gate in a switching element embodied as a MOSFET. During active blocking, a defined voltage, in particular also 0 V, is applied. The defined voltage is selected in such a way that the switching element blocks.In one method step, the reduction of the current, in particular the current intensity, by the central switching element takes place in such a way that the low-side and / or high-side switching elements can be switched and / or blocked and / or that the control unit receives sufficient energy to carry out the actuation of the central switching element and / or of the high-side and / or low-side switching elements.In an advantageous refinement, the blocking of the high-side or low-side switching elements comprises providing a control signal. In particular, the control signal has the effect that no voltage or a voltage less than a threshold voltage is present at the switching input of the switching element. Preferably, the control signal does not cause current to be generated by the blocked high-side or the blocked low-side switching element. Preferably, the current is zero or almost zero. The control signal can be embodied in particular as a voltage which is applied. Preferably, the blocked switching element is controlled in such a way that it is non-conductive.In an advantageous development, the switching of the high-side or low-side switching elements comprises providing a control signal. In particular, the control signal has the effect that a voltage which is equal to or greater than a threshold voltage is present at the switching input of the switching element. The control signal preferably enables a current, in particular a current flow, through the switched high-side or the switched low-side switching elements. In particular, the switched switching element is conductive. The maximum current that arises, in particular the maximum current that arises, is dependent on the actuation of the switching element, in particular dependent on the control signal provided. In particular, switching can also be referred to as switching on or conductive switching.An advantageous development is that the current, in particular the current intensity, flowing through the central control element is reduced to less than 40 mA, preferably less than 30 mA, for example less than 20 mA.An advantageous development is that the method steps are carried out when the engine control unit is operated in standby operation.Exemplary embodiments are illustrated in the figures and explained in more detail in the following description. The following are shown: FIG. 1 is a schematic structure of an engine control unit; and FIG. 2 shows a method according to the invention.FIG. 1 shows a motor control unit 1 according to the invention for controlling an electric motor 5, in particular an electrically commutated electric motor. The electrically commutated electric motor 5 preferably has three phases U, V, W.The engine control unit 1 comprises at least one output stage 10, a control unit 30, a first supply line 40 and a second supply line 42.The first supply line 40 and the second supply line 42 preferably serve to supply the output stage 10 and the control unit 30 with electrical energy. Preferably, the first supply line 40 is connected to the positive pole of an electrical voltage supply 50, in particular a battery. Preferably, the second supply line 42 is connected, in particular electrically connected, to the negative pole of the electrical voltage supply 50. Alternatively, the first supply line 40 can also be connected to the negative pole and the second supply line 42 to the positive pole. In particular, the output stage 10 is connected to the energy source 50 via the supply lines 40, 42. In particular, the control unit 30 is connected to the energy source 50 via the supply lines 40, 42.The output stage 10 comprises at least two half bridges H 1, H 2. By way of example, the output stage 10 according to FIG. 1 has three half bridges H 1, H 2, H 3. Each half bridge H 1, H 2, H 3 preferably comprises at least two switching elements T 1... T6. The switching elements T 1...T 6 are in particular designed as electrical switching elements, preferably as relays, transistors, field effect transistors, preferably MOSFET, FET, IGBT, thyristor, contactor. The first half bridge H 1 comprises the switching elements T 1 (high-side switching element) and T 2 (low-side switching element). The second half bridge H 2 comprises the switching elements T 3 (high-side switching element) and T 4 (low-side switching element). The third half bridge H 3 comprises the switching elements T 5 (high-side switching element) and T 6 (low-side switching element).A connection point 11, 12, 13 is formed between a high-side switching element and the low-side switching element of a half bridge. Each connection point 11, 12, 13 is connected to at least one phase, in particular a phase connection, of the electric motor 5. The number of half bridges Hx depends on the number of phases of the electric motor 5.The high-side switching elements T 1, T 3, T 5 are electrically connected to the first power supply line 40. The low-side switching elements T 2, T 4, T 6 are electrically connected to the second supply line 42. Preferably, the high-side switching elements T 1, T 3, T 5 are connected to the positive pole of the energy source 50 via the supply line 40. The low-side switching elements T 2, T 4, T 6 are preferably connected via the supply line 42 to the negative pole or the GND of the energy source 50. In this context, a connection is not understood to mean a direct connection. The supply line can also be only a partial section of the connection.In particular, an electrically commutated electric motor 5 preferably has three phases U, V, W. Accordingly, the output stage 10 has three half bridges H 1, H 2, H 3. The three phase currents l U, I V and I W. flow through the phases U, V, W. The phases in the electric motor can be interconnected as a star connection or delta connection. In particular, at least one winding is formed on each phase of the electric motor. The phases are energized by the output stage 10 in such a way that a rotating field is established. The rotating field causes a rotation of the rotor / rotor of the electric motor 5.The switching elements T1... T6 of the output stage 10 are controlled by a control unit 30. Preferably, the control unit 30 has a control connection 31, 32, 33, 34, 35, 36 for each switching element T 1...T 6. Each control terminal 31, 32, 33, 34, 35, 36 is connected to a switching element T 1-T 6, in particular the gate terminal (for example T 5- 01; it behaves the same for the other switching elements) of a switching element.The control unit 30 provides a control signal. The providing includes generating and transmitting to the switching elements T 1...T 6. The control unit 30 provides switching patterns for all the switching elements T 1 to T 6 of the half bridges H 1 to H 3.The control unit 30 has supply connections 37, 38. The supply connections 37, 38 serve to supply the control unit 30 with electrical energy. The first supply terminal 37 is connected to the electrical voltage supply 50 via the first supply line 40. The second supply terminal 38 is connected to the electrical voltage supply 50 via the second supply line 42.A central switching element 60 is formed in particular in the first supply line 40 or the second supply line 42. The central switching element 60 is in particular designed as a relay, transistors, field effect transistors, preferably MOSFET, FET, IGBT, thyristor, contactor. The central switching element 60 makes it possible to control, in particular regulate, the current, in particular the current flow, preferably the current intensity, to the control unit 30 and the output stage 10. In particular, it makes it possible to control the current intensity. In particular, it makes it possible to control the voltage which results at the output stage 10. The central control element 60 is preferably designed as a polarity reversal protection switching element. In the blocked state, central switching element 60 disconnects output stage 10 and control unit 30 from energy source 50.The central switching element 60 is preferably arranged upstream of one of the supply connections 37, 38 of the control unit 30 and / or of the output stage 10 in one of the supply lines 40, 42. In particular, the central switching element 60 is arranged between the electrical energy supply 50 and one of the supply connections 37, 38 of the control unit 30, in particular a connection point of the control unit 30, on one of the supply lines 40, 42.The central switching element 60 is controlled by the control unit 30.The central switching element 60, as well as the switching elements T 1...T 6, enable and / or control the current, in particular control the current intensity (conducting) or blocking, or interrupt such a current. Whether the switching element T 1...T 6 or the central switching element 60 enables, controls or blocks a current, in particular a current flow, depends on the actuation at the gate terminal (for example. T5-01). It also depends on the type of switching element T 1...T 6 or of the central switching element 60. In an n-channel MOSFET, the current is interrupted or blocked when the voltage at the gate (for example. T5-01) is less than a threshold voltage (determined voltage, threshold voltage). If, on the other hand, the voltage is greater than a threshold voltage, the n-channel MOSFET becomes conductive. An increase in the gate voltage (gate source voltage) leads to a reduction in the resistance (between drain and source), which in turn leads to an increase in the possible current. FIG. 1 shows the names for the switching element T 5 by way of example. T5-01 is the gate. T5-02 is the source and T5-03 is the drain. For the sake of clarity, the detailed designation of the further shift elements T 1, T 2, T 3, T 4, T 6 and the central shift element has been omitted.The central control element 60 is preferably controlled by means of the control unit 30. the control unit 30 provides a control signal for this purpose, in particular.The control signals for controlling the switching elements T 1...T 6 and the central control element 60 in accordance with the application of a voltage having a defined value, in particular a defined voltage, to the switching elements T 1...T 6 or the central control element 60.Optionally, a further control unit 70 is formed. The further control unit 70 has, in particular, a timer. Furthermore, the further control unit 70 has, in particular, a communication interface 72. The communication interface 72 enables communication with other control units, in particular control units, preferably engine control units, of the vehicle. The communication interface 72 enables communication by means of CAN, LIN, MOST or another bus, or another communication standard, such as Ethernet or the like. Furthermore, the further control unit 70 has, in particular, a connection 74 for an external clock generator. The further control unit preferably has an internal clock generator. The further control unit 70 provides the control unit 30 with a PWM signal. The PWM signal is generated by the further control unit as a function of the clock signal of the clock generator and / or the communication via the communication interface 72, in particular as a function of a received command.The control unit 30 and the further control unit 70 each have a microcontroller or microprocessor.According to an advantageous development, the control unit 30 and the further control unit 70 are designed as one component.FIG. 2 schematically illustrates the method 100 according to the invention.In a method step 110, the high-side switching elements T 1, T 3, T 5 are blocked. The blocking is effected in particular in that, when n-channel MOSFETs are used, a voltage lower than the threshold voltage is applied or applied to the gate.The blocking takes place in that a voltage is present which is smaller than a threshold voltage, in particular switching voltage. The threshold voltage, in particular switching voltage, is the voltage at which the switching element allows a current, in particular a current intensity greater than a defined limit.The blocking of the high-side switching elements T 1, T 3, T 5 thus comprises providing a control signal, in particular a voltage, which has the effect that the high-side switching elements T 1, T 3, T 5 do not permit any current, in particular a current flow between source and drain. The blocking prevents a current, in particular a current flow through the switching element. Consequently, no current can flow to the electric motor 5 via one of the high-side switching elements T 1, T 3, T 5.In a method step 120, the switching of the low-side switching elements T 2, T 4, T 6 takes place. The switching is effected in particular in that, when n-channel MOSFETs are used, a voltage greater than / equal to the threshold voltage is applied or applied to the gate. A voltage is applied which is equal to or greater than the threshold voltage, in particular switching voltage. Switching the low-side switching elements T 2, T 4, T 6 causes a current to be able to form through the low-side switching elements T 2, T 4, T 6.In an alternative method sequence, the blocking 110 of the low-side switching elements T 2, T 4, T 6 and the switching 120 of the high-side switching elements take place.In method step 110, the low-side switching elements T 2, T 4, T 6 are blocked. In method step 120, the switching of the high-side switching elements takes place.In a further method step 130, the supply current is reduced. Method step 130 may also be performed before one or both of method steps 110 and 120. The reduction is effected by a corresponding provision of a control signal to the central switching element 60. The reducing is performed by reducing the gate voltage of the central switching element 60.In an alternative embodiment, the central switching element 60 has a bypass circuit. The bypass circuit allows minimum current. The minimum current is selected such that method steps 110 and 120 can be carried out and the control unit receives sufficient energy for driving the central switching element 60. The minimum current intensity is preferably selected such that it is sufficient to supply the central control element and / or the output stage and / or the control unit. The reduction of the current, in particular the current intensity, by the central switching element 60 is then implemented in particular by blocking the central switching element 60. At the same time, there is a minimum current, in particular a minimum current intensity, via the bypass circuit. The bridging circuit can in particular comprise a diode. In a bypass shift, the central shift element 60 can be blocked.In method step 130, the current is reduced in such a way that low-side switching elements T 2, T 4, T 6 or high-side switching elements T 1, T 3, T 5 can be switched. The current, in particular the current intensity through the central switching element, is preferably reduced to less than 40 mA, in particular 30 mA, preferably 20 mA.The method 100 causes the electric motor 5 to be blocked in an energy-saving manner. The method 100 is necessary in particular in the case of windshield wiper motors which drive a windshield wiper. In this case, a wiper arm must be held in a parking position. This is particularly the case when the vehicle is operated but there is no rain. The wiper arm is then moved into a parking position. The motor control unit is operated in a standby mode.In an optional method step 140, it is detected whether the engine control unit 1 is in standby operation. The ascertainment is effected in particular by monitoring the communication via the communication interface. In standby operation, as described above, the current to the control unit 30 and the output stage 10 is reduced by means of the central control unit 60. Method 100 is preferably carried out at the beginning of the standby operation.

Claims

Motor control unit (1) for controlling an electric motor (5), comprising: • an output stage (10) having at least two half bridges (H1, H2, H3), wherein each half bridge (H1, H2, H3) comprises at least one low-side switching element (T2, T4, T6) and at least one high-side switching element (T1, T3, T5), and wherein a connection point (11, 12, 13), in particular for establishing a connection to the electric motor (5), is formed between the low-side switching element (T2, T4, T6) and the high-side switching element (T1, T3, T5) of each half bridge (H1, H2, H3), • a control unit (30), A motor control unit (1) comprising a central switching element (60) which is formed in the first supply line (40) or the second supply line (42), wherein the central switching element (60) is controlled by the control unit (30), and wherein the central switching element (60) is formed and configured to control current, in particular the current intensity, to the control unit (30) and the output stage (10).Motor control unit (1) according to the preceding claim, characterized in that a further control unit (70) is formed, which in particular provides a PWM signal to the control unit (30), and in that the control unit (30) is formed and configured to actuate the central switching element (60) and / or the output stage (10) on the basis of the provided PWM signal.Engine control unit (1) according to the preceding claim, characterized in that a further control unit (70) is formed, which has a communication interface (72), wherein the communication interface (72) is formed and configured to receive a control signal from a further control unit, in particular an engine control unit.Method (100) for reducing the energy of an engine control unit (1), in particular in standby operation, wherein the engine control unit (1) has an output stage (10), a control unit (30), a first supply line (40) and a second supply line (42) and a central switching element (60), wherein the output stage (10) comprises at least two half bridges (H1, H2, H3), wherein each half bridge (H1, H2, H3) comprises at least one low-side switching element (T2, T4, T6) and at least one high-side switching element (T1, T3, T5), and wherein between the low-side switching element (T2, T4, T6) and the high-side switching element (T1, T3, T5) a half bridge (H1, H2, H3) a connection point (11, 12, 13), in particular for establishing a connection with the electric motor (5), and wherein the control unit (30) is configured to actuate the low-side switching elements (T2, T4, T6) and high-side switching elements (T1, T3, T5), and wherein the first supply line (40) and the second supply line (42) supply the output stage (10) and the control unit (30) with energy, and wherein the central switching element (60) is configured in the first supply line (40) or the second supply line (42), comprising the steps: • blocking (110) the high-side switching elements (T1, T3, T5) and switching (120) the low-side switching elements (T2, T4, T6), or blocking (110) the low-side switching elements (T2, T4, T6) and switching (120) the high-side switching elements (T1, T3, T5); • reducing (130) the current, in particular the current intensity, by the central switching element (60) in such a way that the low-side or high-side switching elements can be switched and / or blocked.Method (100) according to the preceding claim, characterized in that the blocking (110) comprises providing a control signal, wherein the control signal causes blocking.Method (100) according to one of claims 4 to 5, characterized in that the switching (120) comprises providing a control signal.Method (100) according to one of Claims 4 to 6, characterized in that the current, in particular the current intensity, through the central control element (60) is reduced to less than 40 mA, preferably less than 30 mA, for example less than 20 mA.Method (100) according to one of Claims 4 to 7, characterized in that the method (100) is carried out when the engine control unit (1) is operated in the standby mode.

Images