Electric drive unit

Abstract

An electric drive device (1, 2, 3, 100) comprising an inverter (2) controllable for outputting several phase currents (Iu, Iv, Iw), an electric machine (3) energized by the phase currents (Iu, Iv, Iw), and a control device (100) for controlling the inverter (2), wherein the control device (100) is configured to regulate an actual value (Idact, Iqact) of a control variable (Id, Iq) determining the rotary drive of the electric machine (3) to a predetermined setpoint (Idsp, Iqsp) of this control variable (Id, Iq) in a control loop (20, 30, 40, 50, 60, 70, 80, 90) when the electric machine (3) is energized with the phase currents (Iu, Iv, Iw), and wherein the control device (100) is further configured to detect electrical disturbances at a to reduce the supply input of the inverter (2), characterized in that the inverter (2) and the electrical machine (3) are designed such that when the inverter (2) is controlled, the phase currents (Iu, Iv,Iw) can be set individually and independently of each other, and that the control device (100) is further configured to provide a common DC component in all phase currents (Iu, Iv, Iw) when controlling the inverter (2) and to vary this DC component to reduce electrical disturbances at the supply input of the inverter (2).

Description

[0001] The present invention relates to an electric drive device according to the preamble of claim 1, for example for use in a drive train of a vehicle for driving the vehicle.

[0002] In such a drive system, a controllable inverter, supplied on its input side (e.g., by an electric battery), is controlled by a control unit, and a multi-phase electric machine (e.g., an AC synchronous machine) is energized with several phase currents output by the inverter. During this energization of the electric machine, the control unit regulates the actual value of a control variable (e.g., motor current) determining the rotational drive of the electric machine to a predetermined setpoint value of that control variable within a control loop.

[0003] During operation of the drive system, a rotating magnetic field with a desired rotational speed is generated in the electric machine by the multiphase current. In practice, however, this current supply via an inverter also results in electrical interference, which can adversely affect the operation of other technical equipment in the installation environment of the drive system (EMC issues) and can also cause, for example, electrical losses, noise, and other undesirable side effects in the drive system.

[0004] In particular, unwanted electrical disturbances in the form of harmonics often occur, which are additionally caused by nonlinear effects (e.g. within the electrical machine) with respect to a fundamental frequency corresponding to the current rotational speed of the rotating field.

[0005] Electrical disturbances can occur, particularly in the area of ​​a DC voltage supply of the inverter, for example as AC components occurring at the supply input of the inverter, which cause, for example, so-called "ripples" in the time course of the current and / or the voltage at the supply input of the inverter.

[0006] Various concepts are known from the prior art of drive devices of the type of interest here to reduce such electrical disturbances at a supply input of the inverter and thus eliminate or at least mitigate the problems explained above.

[0007] As an example, reference is made to a solution proposed in publication DE 10 2022 210 516 A1. Here, disturbances corresponding to (at least) a specific harmonic are detected, and based on an evaluation of the detected disturbances, a "counter-signal" is generated. This counter-signal is fed into the control loop intended for the control of the electrical machine at a suitable point in order to reduce the disturbances by at least partial compensation (cancellation).

[0008] The concept of feeding a "counter-signal" suitable for canceling out disturbances into the control loop of an electric drive device, e.g., for torque control of the electric machine, is also known from the prior art for reducing so-called "torque ripple" or for reducing associated acoustic noise. In this process, an unwanted disturbance is detected in order to generate a counter-signal that is, in a sense, out of phase (phase-shifted by 180°), which at least partially cancels out the disturbance through destructive interference. Such methods for noise reduction in the operation of an electric machine are known, for example, from publications DE 10 2014 007 502 A1 and DE 10 2018 115 148 A1.

[0009] A disadvantage of this prior art concept, however, is that the intervention in the torque control of the drive unit can disrupt this control. It should be considered that a counter-signal in the control loop, aimed at canceling out disturbances at the inverter's DC supply input, will (at least slightly) affect the torque delivered by the electric machine.

[0010] Another disadvantage is that a certain amount of electrical power is required for interference reduction at the inverter's supply input, which is then no longer available for torque generation. In other words, interference reduction reduces the maximum mechanical drive power that can be delivered by the electric machine.

[0011] It is an object of the present invention to eliminate, in an electric drive device of the type mentioned above, the problems described above which are related to the reduction of electrical disturbances at the supply input of the inverter.

[0012] According to the present invention, this problem is solved in an electric drive device of the type mentioned above by the characterizing features of claim 1. Advantageous embodiments of the invention will become apparent from the dependent claims and the following description.

[0013] The electric drive device according to the invention is characterized in that - that the inverter and the electric machine are designed in such a way that the phase currents can be individually and independently adjusted when controlling the inverter, and - that the control device is designed to provide a common DC component in all phase currents when controlling the inverter and to vary this DC component to reduce electrical disturbances (in current and / or voltage) at the supply input of the inverter.

[0014] A key feature of the invention is that the inverter and the electric machine are designed such that the phase currents can be individually and independently adjusted. This is not conventionally possible because the winding arrangement (e.g., stator winding arrangement) of a multi-phase electric machine is usually configured either in a star configuration or a polygon configuration (e.g., delta configuration), in which the phase currents are mutually dependent, for example, because the sum of the phase currents is zero at any given time. Therefore, they cannot be individually and independently adjusted. This is also unnecessary for generating the rotating magnetic field required to operate the electric machine.

[0015] In the invention, however, this provides the basis for the essential further measure, which consists of providing a common DC component in all phase currents when controlling the inverter for the purpose of reducing electrical disturbances at the inverter's supply input and varying (modulating) this DC component in a suitable manner.

[0016] The "common DC component in all phase currents" means that each phase current contains a DC component in addition to the (e.g., sinusoidal) AC component, so that the sum of these DC components forms a "common DC component." Preferably, the respective DC components of the individual phase currents are equal in magnitude at all times.

[0017] The alternating current components in the phase currents are crucial for generating the rotating magnetic field and thus determine the torque provided by the electric machine. In contrast, the common direct current component in all phase currents, or the individual direct current components within the phase currents, make a kind of "steady-state contribution" to the magnetic field and therefore do not influence the torque provided by the electric machine. This also applies if the common direct current component is varied, as provided for in the invention.

[0018] However, since the common DC component in all phase currents (as well as the AC components contained in the phase currents) is also supplied by the inverter from a DC supply, this common DC component also influences the DC supply current flowing at the inverter's DC supply input. Therefore, the (temporal) variation of the common DC component provided according to the invention is ideally suited for a "torque-neutral" reduction of electrical disturbances at the inverter's supply input. This reduction also allows, for example, a smaller and thus more cost-effective capacitor (intermediate link capacitor) provided at this supply input.

[0019] The variation of the common DC component provided according to the invention acts as a kind of "counter-signal" by which the disturbances at the supply input of the inverter can advantageously be at least partially compensated (eliminated).

[0020] The present invention thus presents a fundamentally novel approach to reducing electrical interference at the inverter's supply input. Advantageously, the invention enables the reduction of electrical interference at the inverter's supply input without interfering with the torque control of the drive unit. Furthermore, although the interference reduction according to the invention also requires electrical power, this advantageously leaves torque generation and the maximum achievable mechanical drive power of the electric machine unaffected, provided the inverter's DC supply (e.g., from an electric battery) is sufficiently powerful.

[0021] Regarding the specific design of the variation of the common DC component required to reduce interference, it is advantageous, for example, to draw on prior art dealing with the detection of interference and the generation of a suitable "counter-signal" for interference suppression, such as the aforementioned publication DE 10 2022 210 516 A1. Such a counter-signal can be used within the scope of the invention to modulate (variete) the common DC component in the phase currents.

[0022] For example, by evaluating one or more recorded electrical quantities, electrical disturbances corresponding to one or more harmonics with respect to a fundamental frequency defined by the instantaneous rotational speed of the electrical machine (e.g., rotor speed in a synchronous machine) can be detected. Based on this, the counter-signal can be generated in such a way that it contains the relevant frequency component(s), and the variation of the track current component according to the counter-signal suppresses the harmonic(s).

[0023] However, within the scope of the invention, other electrical disturbances besides the aforementioned harmonics of the fundamental frequency can also be reduced, for example, disturbances that arise in connection with a clocked control (e.g., PWM control) of the inverter. This includes, for example, the suppression of a disturbance at a specific PWM switching frequency (and, if applicable, sideband and multiples thereof) by a counter-signal whose frequency(ies) and phase(s) are adjusted for disturbance reduction.

[0024] In all cases, alternatively or in addition to electrical quantities such as (at least) a voltage and / or (at least) a current detected in the area of ​​the inverter (inverter input and / or inverter output), electrical signals provided or obtainable in the area of ​​the control device (e.g. control signals for the inverter) can also be evaluated in order to generate the counter-signal on the basis of this.

[0025] In one embodiment of the invention, the inverter comprises first and second inverter sections that can be supplied with a common DC supply voltage (e.g., battery voltage) and each have a number of half-bridge circuits arranged in parallel to each other corresponding to the number of phase currents, wherein the half-bridge circuits are each formed from a series connection of two controllable switches with a central tap between the switches and these central taps can each be connected to or are connected to an associated phase line.

[0026] The center taps can, for example, each be electrically connected to one end of an associated phase line that runs over a winding of the electrical machine.

[0027] Such an inverter can also be referred to as a "dual inverter" in view of the two inverter parts, each of which already possesses the functionality of an inverter.

[0028] With this embodiment, the inverter makes it possible to adjust the phase currents for a winding arrangement of the electric machine individually and independently of each other.

[0029] Between a center tap of a half-bridge circuit of the first inverter part and a center tap of an associated (i.e., pertaining to the same phase) half-bridge circuit of the second inverter part, a respective phase voltage can be provided, which is applied via the respective phase line to a winding of the winding arrangement of the electrical machine in order to energize this winding with the respective phase current.

[0030] Let's assume the inverter is to supply, for example, a three-phase current to the electric machine, or three phase voltages for three corresponding windings of the electric machine. In this case, each of the two inverter sections has three half-bridge circuits, and the following occurs: - a first phase line starting from a center tap of a first half-bridge circuit of the first inverter section via a first winding to a center tap of a first half-bridge circuit of the second inverter section, - a second phase line starting from the center tap of a second half-bridge circuit of the first inverter section via a second winding to the center tap of a second half-bridge circuit of the second inverter section, and - a third phase line starting from the center tap of a third half-bridge circuit of the first inverter part via a third winding to the center tap of a third half-bridge circuit of the second inverter part.

[0031] The two switches of each half-bridge circuit can be controlled complementarily by a respective control signal (in particular, for example, a PWM control signal) to alternately switch the potential of the respective center tap between the positive and negative potential of the DC supply voltage of the inverter.

[0032] This allows, in inverter operation, the two DC potentials at the ends of each of the three windings of the electric machine, and thus the corresponding phase voltage, to be set, in principle, completely arbitrarily within the range defined by the DC supply voltage. In particular, this makes it possible to supply three phase currents that not only each contain an AC component (for example, in a conventional three-phase supply, sinusoidal phase currents that are phase-shifted by 120° relative to each other), but also a common DC component (which, according to the invention, is varied in a manner suitable for interference reduction).

[0033] In contrast to the above example of a three-phase power supply, this power supply and, consequently, the electrical machine can also be designed with a different number of phases (e.g., 4, 5, or 6 phases). In this case, the number of half-bridges in each inverter section, the number of phase lines, and the number of windings of the electrical machine must be adjusted accordingly.

[0034] In a preferred embodiment of the invention, the inverter is controlled by means of PWM control signals, which, for example, have a frequency of at least 1 kHz, for example, on the order of about 10 kHz. Alternatively, it may be provided, for example, that this frequency is at most 50 kHz or at most 25 kHz.

[0035] In one embodiment, the electrical machine has a number of windings corresponding to the number of phase currents, each with its own first and second winding connections, and these winding connections can each be connected to or are connected to an associated line leading to the inverter.

[0036] The two winding terminals of each winding of the electric machine can, for example, be connected to two lines leading to the inverter, which together form a corresponding phase line, along which the respective winding is also located. This means that for a given number of phases (e.g., 3), the same number (e.g., 3) of phase lines and windings are used, but twice the number (e.g., 6) of lines running between the inverter and the electric machine.

[0037] With this embodiment, the phase currents of the electric machine can be set individually and independently of each other.

[0038] In one embodiment of the invention, it is provided that the control device is further configured to regulate an actual value of the common DC component in the phase currents in a control loop to a predetermined setpoint of this DC component when the electric machine is energized, and to vary this setpoint to reduce disturbances at the supply input of the inverter.

[0039] In one embodiment of this design, the actual value and the setpoint of the common DC component are represented in a time domain, i.e., as time-dependent quantities representing these values. Within the control loop, a controller (e.g., a P, PI, or PID controller) can then generate a control variable, also represented in a time domain, based on a detected deviation between the actual value and the setpoint. This control variable determines the common DC component to be supplied when energizing the electric machine. This control variable can then be fed, for example, to a modulator of the control unit as an additional input signal. This modulator then generates control signals (e.g., the aforementioned PWM control signals) that the control unit outputs to the inverter.The modulator then generates the control signals in such a way that the phase currents contain both the AC component (for generating the rotating field) and the DC component (for reducing interference).

[0040] In another embodiment of this design, the actual value and the setpoint of the common DC component are each provided as an "additional component" in a space vector representation, in which an actual value and a setpoint of the control variable (e.g. motor current) determining the rotary drive (e.g. torque) of the electric machine are also provided within the framework of a control of this control variable in a control loop.

[0041] In the control loop, the aforementioned component representing the DC component can, mathematically speaking, be provided or processed orthogonally to both a "d-component" and a "q-component", which (d- and q-components) are conventionally often used in so-called "vector control" to represent two orthogonal components of the motor current in a coordinate system that rotates with the rotating field (and in the case of a synchronous machine also with the rotor).

[0042] In the invention, a control loop with a "vector control" (with space vector representation of certain quantities) can thus be provided in the control device and implemented, for example, by means of software, in which an actual value and a setpoint value of the motor current (total of the phase currents) are represented as a three-dimensional space vector, i.e., encompassing both the conventional "d- and q-components" for representing the current components that determine the "alternating component" and thus the rotating field, as well as a component subsequently also referred to as the "0-component" for representing the current component that determines the "common DC component".

[0043] Within the control loop, a controller (e.g., P, PI, or PID controller) can generate a three-dimensional control variable (with d, q, and 0 components), also represented as a space vector, based on a detected deviation between the actual and setpoint values. This control variable determines the AC and DC components to be supplied to the electric machine. This three-dimensional control variable, or three-component control variable, can be fed as an input signal to a modulator, which then generates control signals (e.g., the aforementioned PWM control signals) that the control device outputs to the inverter. The modulator generates these control signals so that the phase currents contain both the AC and DC components.

[0044] In one embodiment of the invention, the control device is designed to vary the DC component based on a measurement and evaluation of the voltage and / or current at the supply input of the inverter.

[0045] By measuring these electrical quantities at the supply input, the electrical disturbances to be reduced can be detected almost directly and therefore precisely, e.g. specifically regarding one or more harmonics of the fundamental frequency, in order to generate, based on the evaluation of these quantities or disturbances (e.g. regarding amplitude and phase of the harmonic(s)), a "counter-signal" can be generated, by means of which the common DC component is controlled and varied in such a way that the disturbances are reduced, i.e. at least partially canceled out.

[0046] Such a counter-signal can, for example, represent the "setpoint of the common DC component" in the embodiment already explained above, in which an actual value of the common DC component in a control loop is regulated to a predetermined setpoint of this DC component.

[0047] In one embodiment of the invention, the control device is designed to vary the DC component based on a measurement and evaluation of the phase currents.

[0048] This allows the electrical disturbances to be reduced (at the inverter's supply input) to be indirectly detected. This is possible because the time-dependent voltage and current profiles at the supply input are largely determined by the time-dependent phase current profiles. For example, the current flowing at the supply input essentially corresponds to the sum of the phase currents, taking into account the switching states (PWM control signals). However, deviations between this phase current sum and the DC supply current arise, for example, from a "filtering effect" of an arrangement of inductive and / or capacitive elements within the inverter. In practice, such a "filter arrangement" is defined by the specific design (e.g., component properties) and circuit topology of the inverter. For example, individual conductor sections within the inverter can be used for the relevant (often, for example,relatively high or high-frequency frequencies act as inductors. Furthermore, the capacitance of a so-called intermediate circuit capacitor, typically located at the inverter's supply input (between the two DC supply terminals), must be taken into account for the filtering effect of this arrangement.

[0049] In one embodiment, the measured phase currents are evaluated using a (mathematical, e.g., empirically determined) model that describes the time course of the voltage and / or current at the inverter's supply input as a function of the phase currents. In a preferred further development, control signals used to drive the inverter to energize the electric machine are also considered as input variables to the model, in addition to the phase currents. In the case of PWM control signals, the timing of the signal edges in the PWM control signals can provide valuable information regarding the accuracy of the evaluation result.

[0050] Based on electrical quantities (voltage and / or current) determined indirectly in this way (e.g., using the aforementioned model) at the inverter's supply input, this embodiment can also generate a "counter-signal" by evaluating these quantities. This counter-signal is then used to vary the common DC component in a way suitable for interference reduction, thereby at least partially eliminating the interference. The counter-signal can, for example, represent a "setpoint for the common DC component" within the framework of a control system for this DC component.

[0051] In one embodiment of the invention, the control loop for controlling the control variable determining the rotary drive (e.g. torque) of the electric machine comprises: - a comparison device for detecting a deviation between the actual value and the target value of the control variable determining the rotary drive of the electric machine, - a controller for generating control signals based on the deviation detected by the comparator, - a modulation device for generating control signals (e.g., one PWM signal per phase) based on the control signals generated by the controller for controlling the inverter, and - a detection device for recording the actual value of the control variable that determines the rotary drive of the electric machine.

[0052] Preferably, the quantities to be processed in a controlled system and its feedback loop are partially processed in a space vector representation. For example, a representation of the motor current (the totality of phase currents) known from vector control systems can be used, with a d-component and a q-component, which denote the components of the motor current in a coordinate system rotating with the rotating magnetic field. To implement this, the control loop can further include: - a transformation device for the inverse Clarke transformation of the control signals into control signals in a stationary coordinate system according to a vector control, taking into account a rotor rotation angle of the electric machine (the resulting control signals can be fed to the aforementioned modulation device, for example), and - a transformation device for the Clarke-Parks transformation of the phase currents detected at the electric machine into the actual value of the control variable, taking into account the rotor rotation angle of the electric machine (The actual value thus obtained can be supplied, for example, to the aforementioned comparison device).

[0053] In a further development of such a control loop with a space vector representation, particularly of the actual and setpoint values ​​of the aforementioned control variable (e.g., motor current), this representation is extended to a "three-dimensional" space vector representation with d, q, and 0 components, where the 0 component serves to indicate the quantities relating to the DC component. In this case, the control variable regulated in the control loop can then determine the AC and DC components to be provided when energizing the electric machine. The control variable can be fed to the modulator as an input signal, which generates the control signals to be output to the inverter (e.g., PWM control signals, e.g., one control signal per phase).

[0054] In particular, it can therefore be provided that the control loop is designed to additionally (in addition to controlling the control variable determining the rotary drive) regulate an actual value of the common DC component in the phase currents to a predetermined setpoint of this DC component.

[0055] According to a further aspect of the present invention, the use of an electric drive device of the type described herein on board a vehicle is proposed, in particular its use in a vehicle's drive train for propelling the vehicle.

[0056] According to another aspect, a computer program product is comprehensively proposed as program code which, executed on a data processing device (e.g. microcontroller or the like) in a control device of the type described here, provides the described variation of the common DC component in the phase currents to reduce electrical disturbances at the supply input of the inverter.

[0057] The invention is further described below with reference to exemplary embodiments and the accompanying drawings. These schematically represent: Fig. 1 a block diagram of a powertrain of a vehicle with an electric machine and other components of a drive system according to an exemplary embodiment, Fig. 2 a circuit diagram of an inverter with an electrical machine connected to it according to an exemplary embodiment, and Fig. 3 a block diagram of a control device in a drive system according to an exemplary embodiment.

[0058] Fig. Figure 1 shows an embodiment of a drive train 4 of a vehicle and other components of a drive system of the vehicle.

[0059] The in Fig. The drive train 4 shown in Figure 1 comprises an electric machine 3 (e.g., a three-phase AC synchronous machine), a shaft driven by it, and, further along the drive train 4, as shown, for example, a reduction gear 5 and a differential gear 6 for distributing torque to two wheels 7 of the vehicle. This differs from the illustration in Figure 1. Fig. 1. The gearbox 5 could also be implemented, for example, structurally combined with the electric machine 3.

[0060] In the illustrated embodiment, the vehicle is an electric vehicle, e.g., a battery electric vehicle (BEV), which can be driven by the electric machine 3 via the illustrated drive train 4. During operation of the drive system, the electric machine 3 provides a desired torque Tq to the drive train 4.

[0061] The in Fig. The drive system shown in Figure 1 further comprises an inverter 2 for generating a multi-phase motor current for the electric machine 3, in the example a three-phase AC current with three components (phase currents) Iu, Iv, Iw.

[0062] For the electrical supply of the inverter 2, the drive system also includes an electric battery 1, whose battery voltage provides a DC supply voltage with potentials DC+ and DC- for the inverter 2.

[0063] The drive system also includes a control device 100, by means of which the electric machine 3 is controlled via the inverter 2.

[0064] In the illustrated example, the control unit 100 is implemented by a software-controlled computing device located on board the vehicle, such as one (or more interconnected) microcontrollers or another digital signal processing device. The control unit 100 can, for example, communicate with a vehicle control unit (not shown) to receive a setpoint for the aforementioned desired drive torque Tq via this communication link. Based on this setpoint for Tq, the control unit 100 generates three control signal components or signals Cu, Cv, Cw for the inverter 2, with each of these components Cu, Cv, Cw serving to control one of the three phase currents Iu, Iv, Iw.

[0065] The drive system can implement a "motor operation" of the electric machine 3, in which energy is transferred from the battery 1 to the electric machine 3 via the inverter 2. Furthermore, a "generative operation" of the electric machine 3 can also be implemented, in which energy is transferred from the electric machine 3 to the (rechargeable) battery 1 via the inverter 2 (recuperation operation of the vehicle).

[0066] Fig. Figure 2 shows an example circuit diagram for the drive system of Fig. 1 used inverter 2 together with the electrical machine 3 connected to it via phase lines for phases U, V and W.

[0067] In the example shown, inverter 2 comprises a first inverter part 2a and a second inverter part 2b. As shown, the two inverter parts 2a and 2b have an identical structure and are supplied with a common DC supply voltage UDC, corresponding to the battery voltage with the potentials DC+ and DC-, during operation of the drive system.

[0068] Each of the two inverter parts 2a, 2b has a number of half-bridge circuits arranged in parallel to each other corresponding to the number of phase currents Iu, Iv, Iw, in the example of three phases U, V, W thus three half-bridge circuits.

[0069] The half-bridge circuits are each supplied by the DC voltage UDC and each consists of two controllable switches (here: MOSFETs) connected in series with a center tap between the switches. Each center tap is connected to an associated line leading to the electrical machine 3. In this way, the three phase lines, or phases U, V, W, are formed using six such lines.

[0070] In this example, the electrical machine 3 has a winding arrangement with a number of windings corresponding to the number of phase currents Iu, Iv, Iw, i.e., three windings Wu, Wv, Ww. Each of the windings Wu, Wv, Ww has first and second winding terminals at its ends, which, as shown, are each connected to an associated line leading to inverter 2. For each of the windings Wu, Wv, Ww, the respective first winding terminal is connected via a first section of the corresponding phase line U, V, or W to the first inverter section 2a, and the respective second winding terminal is connected via a second section of the corresponding phase line U, V, or W to the second inverter section 2b, thus forming the three phase lines leading through each of the windings Wu, Wv, Ww.

[0071] With inverter 2, which can also be referred to as a "dual inverter" due to its two inverter sections 2a and 2b, the phase currents Iu, Iv, and Iw for the electric machine 3 can be individually and independently adjusted. For this purpose, a respective phase voltage is provided between a center tap of a half-bridge circuit of the first inverter section 2a and a center tap of a corresponding half-bridge circuit of the second inverter section 2b, corresponding to the same phases U, V, and W, respectively. This voltage is then applied via the respective phase lines U, V, and W to the respective winding Wu, Wv, and Ww of the electric machine 3.

[0072] The two switches (here: MOSFETs) of each half-bridge circuit are controlled during operation of the drive system by a respective control signal (see PWM control signals Cu, Cv, Cw in Fig. 1) Complementarily controlled to rapidly alternate the potential of the relevant center tap between the positive supply potential DC+ and the negative supply potential DC- of the DC supply voltage of inverter 2, e.g., with a PWM frequency of approximately 10 kHz. By varying the PWM ratios, the two potentials at the ends of each of the three windings Wu, Wv, Ww, and thus each of the three phase voltages, can be adjusted within the range defined by the DC supply voltage UDC during inverter operation.

[0073] This makes it possible to provide the three phase currents Iu, Iv, Iw not only with their respective, e.g., sinusoidal AC components, but also with an additional common DC component in the phase currents Iu, Iv, Iw. The AC components determine the rotating magnetic field and thus the torque Tq generated in the electrical machine 3 by means of the windings Wu, Wv, Ww. In contrast, the DC components in the three phase currents Iu, Iv, Iw contribute a "torque-neutral" element to the generated magnetic field.

[0074] According to the invention, the common DC component in the phase currents Iu, Iv, Iw is varied over time in a suitable manner to reduce electrical interference. This is possible because any change in the current intensity of the common DC component in the AC phase currents Iu, Iv, Iw, in principle, affects the DC current intensity at the supply input of inverter 2 more or less 1:1. In a dynamic analysis (of the time-dependent behavior of these currents), deviations from this 1:1 relationship do occur, for example, due to the effect of the... Fig. The two visible so-called intermediate circuit capacitors C at the inverter input. However, such deviations can be taken into account, for example, by applying a suitable (mathematical) model to determine (e.g., calculate) a temporal variation of the common DC component in the phase currents Iu, Iv, Iw such that its effect at the supply input of inverter 2 reduces the disturbances occurring there.

[0075] Fig. Figure 3 shows a block diagram of the drive system of Fig. 1. Control device 100 used according to an exemplary embodiment. In the case of an implementation of the control device 100 as a software-controlled computing device, the following are Fig. The components of the control unit 100 shown in the diagram are at least partially realized or understood as components or functionalities of a control program running in the control unit 100.

[0076] The control unit 100 has a control loop to regulate actual values ​​Iqact, Idact, which together form an actual value of a control variable Iq, Id ("AC motor current"), to corresponding setpoint values ​​Iqsp, Idsp, which together form a setpoint of this control variable Iq, Id. The control variable Iq, Id determines, according to a field-oriented vector control, the magnitude of a rotary drive (torque) of the electric machine 3.

[0077] Here, “Id” and “Iq” denote the current components of the phase currents Iu, Iv, Iw that determine the torque Tq in a coordinate system rotating with the generated rotating field, with a “fundamental frequency” corresponding to an instantaneous rotational speed N of the electrical machine 3.

[0078] The actual values ​​Iqact, Idact are calculated by the control unit 100 based on the values ​​of the phase currents Iu, Iv, Iw detected at the electrical machine 3 by means of a current sensing device 60 (Clarke-Parks transformation).

[0079] In this example, the setpoint values ​​Iqsp and Idsp are generated and output by a control unit 10, based on an externally received setpoint for the torque to be generated, Tq. This setpoint can originate from a vehicle control unit (not shown). When generating (e.g., calculating) the setpoint values ​​Iqsp and Idsp, the control unit 10 can also consider other instantaneous operating parameters of the drive system. For example, as shown, the rotational speed N of the electric machine 3, the DC supply voltage UDC of the inverter 2, and / or the value of (at least) one temperature T (e.g., of the electric battery 1, the inverter 2, and / or the electric machine 3) can also be taken into account.

[0080] In the control unit 100 of Fig. 3 is a control loop (20, 30, 40, 50, 60, 70, 80, 90) formed by, among other things, the following devices: - a first transformation device 70 for the Clarke-Parks transformation of the phase currents Iu, Iv, Iw detected at the electric machine 3 by means of the current sensing device 60 into the corresponding actual values ​​Iqact, Idact of the control variable Iq, Id. The transformation takes place taking into account a rotational angle position φ of a rotor of the electric machine 3. - a comparison device 20 with subtraction nodes 21, 22 for comparing the actual values ​​Iqact, Idact with the corresponding target values ​​Iqsp, Idsp, - a controller (here: PI controller) 30 for generating control signals Idctl, Iqctl based on the result of comparing the actual values ​​Iqact, Idact with the setpoint values ​​Iqsp, Idsp, - a second transformation device 40 for the inverse Clarke transformation of the control signals Idctl, Iqctl into control signals α, β in a stationary (stator-fixed) coordinate system according to the vector control, taking into account the rotation angle position φ, - a modulation device 50 for space vector modulation (“space vector PWM”) based on the control signals α, β for generating PWM control signals Cu, Cv, Cw for controlling the inverter 2 for generating the phase voltages and thus the resulting phase currents lu, Iv, Iw.

[0081] A sensor signal representative of the rotational angle φ of the electric machine 3 is obtained by means of a rotational position sensor S arranged on the electric machine 3, e.g., a rotary encoder or so-called "resolver". This signal provides time-resolved information about the rotational position of the rotor of the electric machine 3. In this example, the information about the rotational angle φ is used, for example, to perform the aforementioned mathematical transformations in devices 40 and 70.

[0082] The devices 20, 30, 40, 50, 60, and 70 described above, provided in the control loop, regulate the actual values ​​Iqact and Idact of the control variables Iq and Id, which determine the rotary drive of the electric machine 3, to the corresponding setpoint values ​​Iqsp and Idsp supplied by the input device 10. The control device 100 thus converts the input value received for the torque Tq, in conjunction with the inverter 2 (by outputting suitable control signals Cu, Cv, and Cw to the inverter 2), so that the desired drive torque Tq is achieved in the drive train 4.

[0083] A special feature of the control unit 100 is that it is also designed to reduce unwanted electrical interference at the supply input of inverter 2. In this section of the DC voltage supply of inverter 2 (between the electric battery 1 and inverter 2), electrical interference, particularly in the form of harmonics, can occur with respect to the aforementioned fundamental frequency determined by the rotor rotation. These harmonics manifest themselves at the supply input of inverter 2 as corresponding alternating components (with the frequency(ies) of the harmonics) or as ripples in the time course of a DC current IDC and / or the DC voltage UDC at the supply input of inverter 2. Furthermore, other unwanted interference can be caused here, for example, by the PWM switching operations of the switches controlled in inverter 2.

[0084] The control device 100 is designed to provide the aforementioned "common DC component in all phase currents" Iu, Iv, Iw when controlling the inverter 2 and to vary this DC component to reduce electrical disturbances at the supply input of the inverter 2.

[0085] In the example of Fig. 3. A suitable variation of the DC component is carried out based on a measurement and evaluation of electrical quantities that are detected at the supply input of inverter 2 by means of a detection device 80. The detection device 80 can, for example, measure the voltage UDC and / or the current IDC at the supply input of inverter 2, as shown.

[0086] The evaluation of these recorded quantities UDC, IDC is carried out by a counter-signal generation device 90, which, in addition to this information (UDC and / or IDC), optionally includes the following: Fig. 3 shows, for example, that the sensor signal from sensor S, representative of the rotational angle φ of the electric machine 3, can also be supplied. Furthermore, other information or signals can also be supplied as (additional) input variables for the evaluation carried out by the counter-signal generation device 90, as shown (in Fig. 2 not shown) in particular, for example, the control signals Cu, Cv, Cw.

[0087] Based on this evaluation or processing of all input variables supplied to the counter-signal generation device 90, the counter-signal generation device 90 generates a "counter-signal" as an output variable for interference suppression, which controls the required variation of the common DC component in the phase currents Iu, Iv, Iw.

[0088] In the example shown from Fig. 3 represents this counter-signal as a setpoint I0sp of this DC component used within the framework of a control of the common DC component in the phase currents Iu, Iv, Iw.

[0089] The actual value I0act of the common DC component in the phase currents Iu, Iv, Iw is regulated to the setpoint I0sp in the control loop described above, and this setpoint is varied to reduce disturbances at the supply input of inverter 2. The setting and variation of the setpoint I0sp is accomplished by the counter-signal generation unit 90 based on the aforementioned evaluation of corresponding detection signals (e.g., UDC, IDC) or input variables (e.g., Cu, Cv, Cw).

[0090] The regulation of the common direct current component is achieved by a Fig. 3 evidently implemented correspondingly “extended” training of facilities 20, 30, 40, 50, 70 of the control loop already described above: - The comparison device 20 includes a further subtraction node 23 for comparing the actual value I0act with the target value I0sp. - The controller 30 is designed to generate an additional control signal I0ctl based on the result of comparing the actual value I0act with the setpoint I0sp. - The transformation unit 40 is designed to additionally process the received control signal I0ctl in order to output an additional control signal “0” to the modulation unit 50. - The modulation device 50 for space vector modulation for generating the control signals Cu, Cv, Cw is designed to additionally take into account the supplied control signal “0” in order to provide a common DC component represented by this control signal “0” in the phase currents Iu, Iv, Iw. - The transformation device 70 for transforming the phase currents lu, Iv, Iw detected by means of the current detection device 60 is designed to additionally supply the actual value I0act of the common DC component contained in the phase currents lu, Iv, Iw.

[0091] In summary, in the example of Fig. 3. The actual value I0act and the setpoint I0sp of the common DC component I0 are each provided as an additional component of the space vector representation in which the actual values ​​Idact, Iqact and the setpoint values ​​Idsp, Iqsp of the torque-determining control variable Id, Iq are also represented. In the control loop, in addition to the d and q components of the motor current, a "0 component" representing the DC component I0 is also processed.

[0092] In a opposite Fig. In the modified embodiment 3, it is provided that the detected quantities UDC and / or IDC are not supplied to the counter-signal generation device 90 (thus also rendering the detection device 80 unnecessary), but rather, for example, the detected values ​​of the phase currents Iu, Iv, Iw as well as the control signals Cu, Cv, Cw. Based on an evaluation of these quantities, the correspondingly modified counter-signal generation device 90 can, for example, generate the signal as described in Fig. 3. The intended setpoint I0sp for interference reduction is determined and output.

[0093] In summary, the invention advantageously enables, for example, a reduction of voltage and / or current ripple on the DC supply side (battery side) of an electric machine by operating the machine, for example, with a dual inverter and providing and suitably varying a common DC component contained in all phases. The DC component can be generated with suitable frequency(ies) and phase(s) of variation in such a way that it counteracts the ripple. Reference symbol list 1 electric battery 2 Inverter 2a, 2b first and second inverter parts 3 electric machine 4 Powertrain 5 reduction gears 6 Differential gears 7 vehicle wheels 100 Control unit 10. Setting device 20 Comparative Institution 21, 22, 23 Subtraction nodes 30 PI controllers 40 Transformation facility 50 Modulation device 60 Recording device 70 Transformation facility 80 Recording device 90 Counter-signal generation device S rotation position sensor φ Rotor rotation angle UDC DC supply voltage IDC DC supply current DC+, DC DC supply potentials U, V, W phases Cu, Cv, Cw control signals lu, Iv, Iw phase currents Wu, Wv, Ww windings C capacitor Iq, ID control variable Iqact, Idact Actual values Iqsp, Idsp setpoints Idctl, Iqctl control signals α, β Control signals Iq, ID control variable I0act actual value I0sp setpoint I0ctl control signal 0 control signal Tq torque N speed Temperature QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2022 210 516 A1 [0007, 0021] DE 10 2014 007 502 A1

[0008] DE 10 2018 115 148 A1

[0008]

Claims

[1] Electric drive device (1, 2, 3, 100) with an inverter (2) controllable to output several phase currents (Iu, Iv, Iw), an electric machine (3) energizable with the phase currents (Iu, Iv, Iw), and a control device (100) for controlling the inverter (2), wherein the control device (100) is configured to control an actual value (Idact, Iqact) of a control variable (Id, Iq) determining the rotary drive of the electric machine (3) to a predetermined setpoint value (Idsp, Iqsp) of this control variable (Id, Iq) in a control loop (20, 30, 40, 50, 60, 70, 80, 90) when the electric machine (3) is energized with the phase currents (Iu, Iv, Iw), and wherein the control device (100) is further configured to reduce electrical disturbances at a supply input of the inverter (2), characterized by , that the inverter (2) and the electric machine (3) are designed such that when controlling the inverter (2) the phase currents (Iu, Iv, Iw) can be individually and independently adjusted, and that the control device (100) is further configured to provide a common DC component in all phase currents (Iu, Iv, Iw) when controlling the inverter (2) and to vary this DC component to reduce electrical disturbances at the supply input of the inverter (2). [2] Electric drive device (1, 2, 3, 100) according to claim 1, wherein the inverter (2) has first and second inverter parts (2a, 2b) which can be supplied with a common inverter supply voltage (UDC) and each have a number of half-bridge circuits arranged in parallel to each other corresponding to the number of phase currents (Iu, Iv, Iw), wherein the half-bridge circuits are each formed from a series connection of two controllable switches with a center tap between the switches and these center taps can each be connected to or are connected to an associated phase line. [3] Electric drive device (1, 2, 3, 100) according to claim 1 or 2, wherein the electric machine (3) has a number of windings corresponding to the number of phase currents (Iu, Iv, Iw) with respective first and second winding terminals and these winding terminals are each connected to an associated phase line leading to the inverter (2). [4] Electric drive device (1, 2, 3, 100) according to one of the preceding claims, wherein the control device (100) is further configured to control an actual value (I0act) of the common DC component (I0) in the phase currents (Iu, Iv, Iw) in a control loop (20, 30, 40, 50, 60, 70, 80, 90) to a predetermined setpoint (I0sp) of this DC component (I0) when the electric machine (3) is energized, and to vary this setpoint (I0sp) to reduce disturbances at the supply input of the inverter (2). [5] Electric drive device (1, 2, 3, 100) according to one of the preceding claims, wherein the control device (100) is further configured to perform the variation of the DC component (I0) based on a measurement and evaluation of the voltage (UDC) and / or the current (IDC) at the supply input of the inverter (2). [6] Electric drive device (1, 2, 3, 100) according to one of claims 1 to 4, wherein the control device (100) is further configured to vary the DC component (I0) based on a measurement and evaluation of the phase currents (Iu, Iv, Iw). [7] Electric drive device (1, 2, 3, 100) according to one of the preceding claims, wherein the control loop (20, 30, 40, 50, 60, 70, 80, 90) comprises: - a comparison device (20) for detecting a deviation between the actual value (Idact, Iqact) and the setpoint value (Idsp, Iqsp) of the control variable (Id, Iq) determining the rotary drive of the electric machine (3), - a controller (30) for generating control signals (Idctl, Iqctl) based on the deviation detected by the comparator (20), - a modulation device (50) for generating control signals (Cu, Cv, Cw) based on the control signals (Idctl, Iqctl) generated by the controller (30) for controlling the inverter (2), - a detection device (60) for detecting the actual value (Idact, Iqact) of the control variable (Id, Iq) determining the rotary drive of the electric machine (3), and wherein the control loop (20, 30, 40, 50, 60, 70, 80, 90) preferably further comprises: - a transformation device (40) for the inverse Clarke transformation of the control signals (Idctl, Iqctl) into control signals (α, β) in a stationary coordinate system according to a vector control taking into account a rotor rotation angle (φ) of the electric machine (3), - a transformation device (70) for Clarke-Parks transformation of the phase currents (Iu, Iv, Iw) detected at the electric machine (3) into the actual value (Iqact, Idact) of the control variable (Iq, Id) taking into account the rotor rotation angle (φ) of the electric machine (3). [8] Electric drive device (1, 2, 3, 100) according to claim 7, wherein the control loop (20, 30, 40, 50, 60, 70, 80, 90) is configured to additionally control an actual value (I0act) of the common DC component (I0) in the phase currents (Iu, Iv, Iw) to a predetermined setpoint value (I0sp) of this DC component (I0). [9] Use of an electric drive device (1, 2, 3, 100) according to any of the preceding claims in a drive train (4) of a vehicle for propelling the vehicle. [10] Computer program product comprising a program code which, when controlling the inverter (2) on a data processing device in a control device (100) of an electric drive device (1, 2, 3, 100) according to one of claims 1 to 8, provides a variation of the common DC component in all phase currents (Iu, Iv, Iw) to reduce electrical disturbances at the supply input of the inverter (2).

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