DE102016212852A1 - Drive device for a and method for driving a vehicle arranged in a synchronous machine - Google Patents

Abstract

The present invention relates to a drive device for a vehicle-mounted synchronous machine, wherein the synchronous machine has a rotor and a stator. The vehicle also has an energy supply unit and an inverter, wherein the synchronous machine can be connected to the energy supply unit via the inverter. The drive device is configured to provide drive signals for driving the inverter. For this purpose, it has a setpoint unit and a conversion unit, wherein the setpoint unit is configured to determine a torque current setpoint for a torque-forming current and a field current setpoint for a field-forming current in a normal operating state according to a field-oriented control approach as a function of a default value, and in a from the normal operating state different heating operating state for the torque current setpoint, a time-varying value and for the field current setpoint to specify a time constant value. The conversion unit is set up to determine the activation signals as a function of the torque current setpoint and the field current setpoint. Similarly, the invention also relates to an associated method for driving the arranged in the vehicle synchronous machine.

Description

The invention relates to a drive device for a and a method for driving a vehicle arranged in a synchronous machine.

The majority of vehicles currently in operation, particularly passenger cars, are still equipped with an internal combustion engine which serves to generate at the drive wheels of the vehicle a torque causing a propulsion of the vehicle. In order to comply with the ever more stringent exhaust gas regulations and to further sustainable use of energy resources and thus to protect the environment combustion engines are further and further optimized in terms of their consumption. A side effect is that in particular internal combustion engines with a small displacement, especially auto-igniting internal combustion engines generate less and less waste heat in their operation, for example, measures are taken in appropriately equipped vehicles to heat the interior of the vehicle in a comfortable way for the occupants , In such vehicles for specific heating of the interior, for example, additional, otherwise not required heating elements, preferably Peltier elements installed. On the one hand, this entails additional costs; on the other hand, installation space must be provided for the installation of such components.

Even with the vehicles nowadays increasingly on the market with an electric drive system, this can be hybrid or electric vehicles, there is this problem or challenge. In hybrid vehicles in addition to an internal combustion engine, another unit for the drive is used, usually an electric machine, the combustion engine is designed to be relatively small due to the concept. In a special way, this problem or challenge in electric vehicles, which are driven exclusively by an electric machine; These vehicles lack an internal combustion engine whose waste heat could be used to heat the interior. In hybrid and electric vehicles, the above-mentioned additional heating elements can be used in a corresponding manner.

At this point I would like to take a brief look at hybrid and electric vehicles. The electric drive machines used in these vehicles are supplied with electrical energy from a high-voltage supply unit. Such electrical machines are generally constructed as internal rotor machines, in which a rotatably mounted rotor is enclosed by a stationary stator. As drive machines synchronous machines can be used, which are either permanently excited or energized. A high-voltage supply unit used in this case can have a voltage level of 250 to 420 volts, in some cases even up to 1000 volts. In order to achieve this voltage level, a high-voltage supply unit is constructed from a large number of energy supply cells, for example energy storage cells. Usually, lithium ion storage cells are used for this purpose. Such a constructed high-voltage supply unit is also referred to as high-voltage storage or traction battery.

The above described for the different drive concepts challenge or problem to be able to heat the interior of a vehicle sufficiently, occurs in almost all possible vehicle operating situations, for example, immediately at the start of the journey or a vehicle standstill.

To be able to dispense with the above-mentioned heating elements, and thus to be able to save costs in vehicle production and space, different approaches are pursued. One approach is to use the waste heat generated by an electric machine installed in a vehicle, which is caused by currents flowing in the stator windings thereof and the associated current heat losses, to heat the vehicle interior. Any electric vehicle installed in a vehicle is suitable for this purpose. As long as the electric machine is operated in a normal operating state and thus the rotor performs a rotational movement, there is a uniform or uniformly distributed heating of the stator windings. In this case, the loss of heat generated by the control of the electric machine can be used for heating the vehicle interior without the electrical machine being damaged here. Now, as already indicated, the heating of the vehicle interior to be possible at any time, even if, for example, no normal operating state of the electric machine is present and the rotor is stationary and thus performs no rotational movement. In order to generate current heat losses even with a stationary rotor, which then lead to a usable for the heating of the vehicle interior heat loss, higher-frequency alternating or three-phase currents can be impressed into the stator windings. Through this type of currents, a uniform heating of the stator windings can be achieved even with a stationary rotor. However, due to these higher-frequency alternating or three-phase currents, pulsating torques occur, which then, if it is, for example, a correspondingly large-dimensioned electrical machine, in particular a traction machine, are perceived by the driver as disturbing and thus disadvantageous. In addition, caused by these currents, time-varying stator magnetic field in a permanent magnet synchronous machine lead to eddy current losses in the permanent magnet arranged in the rotor, which can heat them, which is disadvantageous when reaching a temperature characteristic of the respective permanent magnets, as due to the Temperature sensitivity of the materials used can lead to an impairment of the magnetic effect. In a current-excited synchronous machine said stator magnetic field in the rotor arranged on the excitation winding and thus in the exciter circuit can cause high induced voltages, which can lead to problems in the electromagnetic compatibility.

It is therefore an object of the present invention to provide a drive device for a and a method for driving a arranged in a vehicle synchronous machine, with or independent of the operating state of the synchronous machine and / or regardless of driving condition of the vehicle as evenly distributed current heat losses in the synchronous machine can be generated to heat the interior of a vehicle by a heat loss in the electrical machine resulting in any operating conditions of the synchronous machine and / or driving conditions of the vehicle - both when the rotor of the synchronous machine is moving and when it stops, and / or both when the vehicle is moving and when it is stationary.

This object is achieved by a drive device for a vehicle-mounted, a rotor and a stator having and connectable via an inverter with a power supply unit synchronous machine, which is adapted to provide drive signals for driving the inverter, and for this purpose a setpoint unit and a conversion unit, wherein the target unit is configured to determine a torque current command value for a torque-forming current and a field current command value for a field-forming current in a normal operating state in accordance with a field-oriented control approach, and in a heating operating state different from the normal operating state Torque current setpoint a time-varying value and for the field current setpoint to specify a time constant value, and wherein the conversion unit is adapted to i n dependence of the torque current setpoint and the field current setpoint to determine the control signals.

• – Ermitteln eines Drehmomentstromsollwert für einen drehmomentbildenden Strom und eines Feldstromsollwert für einen feldbildenden Strom in Abhängigkeit eines Vorgabewerts in einem Normalbetriebszustand gemäß einem feldorientierten Regelungsansatz, und Vorgeben eines sich zeitlich ändernden Werts für den Drehmomentstromsollwert und eines zeitlich konstanten Werts für den Feldstromsollwert in einem sich von dem Normalbetriebszustand unterscheidenden Heizbetriebszustand,
• – Ermitteln von Ansteuersignalen in Abhängigkeit des Drehmomentstromsollwerts und des Feldstromsollwerts, und
• – Bereitstellen der Ansteuersignale zum Ansteuern des Wechselrichters.

The object is further achieved by a method for controlling a arranged in a vehicle, a rotor and a stator having and solved by appropriately driving an inverter via this connectable to an energy supply unit synchronous machine in which the following steps take place in a drive device:

• Determining a torque current command value for a torque-forming current and a field current command value for a field-forming current as a function of a default value in a normal operating state according to a field-oriented control approach, and setting a time-varying value for the torque current command value and a time-constant value for the field current command value in a of the Normal operating state different heating mode,
• Determining drive signals as a function of the torque current setpoint and the field current setpoint, and
• - Providing the drive signals for driving the inverter.

The approach according to the invention is based on the knowledge that by means of suitable energization of a synchronous machine with this in any driving operating state of a vehicle and / or in any operating state of the synchronous machine a loss of heat can be generated, which can be used for heating the interior of a vehicle. Thus, even in the previously problematic situations in which there is a vehicle standstill and / or the rotor of the synchronous machine is essentially stationary. Since the synchronous machine is driven according to a field-oriented control approach, in the heating operating state, that is to say when heating of the vehicle interior is required or deemed necessary, a suitable specification is made for the two current setpoint values. For the torque current setpoint, a time-varying current and for the field current value, a temporally constant current is specified. The resulting superimposition of a temporally constant field-forming storm and a time-varying current-forming current leads to a suitable control of the inverter, which in turn leads to currents flowing in the stator windings, causing uniform current heat losses and thus uniform heating of the stator windings in the stator windings. As a result, a uniform heating can be achieved for a synchronous machine even when the vehicle is at a standstill and / or when the rotor is stationary. This ensures that even in the past problematic situations in a permanent magnet synchronous machine excessive heating of the permanent magnets is avoided, or in a current-excited synchronous machine excessively large induced voltages in the excitation windings are avoided. It is therefore possible in any driving conditions of the vehicle and / or operating conditions of the synchronous machine, depending on the structure of the synchronous machine without high thermal losses in the permanent magnets or high induced voltages in the field windings to heat the vehicle interior by means of a heat loss generated at the synchronous machine can.

The above object is therefore completely solved.

Before discussing the advantageous embodiments of the invention, explanatory explanations will be given first.

A synchronous machine arranged in a vehicle is in each case associated with a movement functionality, the synchronous machine being energized in a normal operating state in such a way that the movement functionality can be fulfilled by the torque arising at its rotor shaft, for example driving a cooling fan arranged in a cooling circuit or moving a windshield wiper , In the heating operating state, it is now possible to generate current heat losses and thus loss heat by specifying a time constant value for the field current setpoint and a time-varying value for the torque current setpoint in the stator windings, without the synchronous machine generating a torque or at its Rotor shaft applies a torque sufficient to perform the synchronous machine associated motion functionality. With the synchronous machine, a loss of heat can be generated, without causing a significant torque that leads to a perceptible rotational movement of the rotor shaft of the synchronous machine or causes such a.

For the following statements, it is assumed that the synchronous machine has a stator with three stator windings, which is thus a three-phase synchronous machine. The stator windings are energized in such a way that a rotating stator magnetic field is produced. In order for the rotor to follow the rotating stator magnetic field, it must have a rotor magnetic field. The rotor magnetic field can be generated either by means of a rotor winding arranged on the rotor (current-excited synchronous machine) or by means of permanent magnets (permanent-magnet synchronous machine) arranged on the rotor.

The synchronous machine is to be operated according to a field-oriented control approach, which is also referred to as vector control. Ie. In the normal operating state of the synchronous machine, the currents flowing through the stator windings are determined based on a field-oriented control approach. In the field-oriented control approach, the stator-related or stator-fixed three-phase coordinate system is imaged by means of the so-called Clarke transformation and the so-called Park transformation on a rotor-related or rotorfestes two-phase coordinate system in a three-phase synchronous machine rotates with the rotor. The two mutually orthogonal axes of this two-phase coordinate system are referred to as d-axis and q-axis, where the value of the d-axis represents the magnetic flux density of the synchronous machine and the value of the q-axis represents the torque of the synchronous machine. The d-axis is defined as the center of a rotor pole and the q-axis lies between two poles. In this coordinate system, by means of a d-value, i. H. the field-forming current component or the field-forming current, and a q-value, d. H. the torque-forming current component or the torque-forming current, any current value can be represented. For this purpose, a desired value for the field-forming current component or the field-forming current, d. H. a field current setpoint, and a setpoint for the torque-forming current component or torque-forming current, i. H. a torque current setpoint specified. The field-forming current component and the torque-forming current component or the field-forming current and the torque-forming current represent operating variables of the synchronous machine. In the field-oriented control approach, two current setpoint values are determined, namely a torque-forming current setpoint or torque current setpoint and a field-forming current setpoint or field current setpoint, as a function thereof the energization of the stator windings and thus the generation of the rotating stator magnetic field takes place.

The default value may be a value for the torque to be generated by the synchronous machine or for the torque to be provided at the rotor shaft or to be delivered thereto. In this case, the default value can be adapted to changing circumstances during the normal operating state, which means that the default value can change over time in the normal operating state. This in turn means that both the torque current setpoint and the field current setpoint can change over time during the normal operating state can be adapted to changing circumstances. Thus, it is ensured in the normal operating state that the synchronous machine at any time provides the appropriate torque according to the prevailing conditions. In contrast, the heating mode is based on a different approach. In the heating mode, the torque current setpoint and the field current setpoint are not determined as a function of the default value and thus are not adapted continuously to changing circumstances. In the heating operating state, a time-changing value is specified for the torque current setpoint, and a time-constant value is specified for the field current setpoint. In both cases, this does not depend on the default value. In this respect, the heating operating state is based on a modified field-oriented approach. Although two setpoints are used in the heating mode, but they are not determined in dependence on the default value, but in other manner to be described. In the heating mode, the two setpoints are not adaptively adapted to external conditions, as is the case in the normal operating state. Rather, a time characteristic is specified for the three-phase current setpoint and a value for the field current setpoint.

For the two currents given in the rotor-fixed coordinate system, namely the field-forming current and the torque-forming control deviations are determined starting from the two setpoints, namely the torque current setpoint I _qS and the field current setpoint I _dS and the two actual values determined for these currents Inverse Park transformation and an inverse Clarke transformation are transformed back into the stator-related three-phase coordinate system to then be able to determine based on the current values given in this coordinate system control signals for driving the inverter.

As is known, a vehicle has drive wheels. In a preferred embodiment of the invention, the synchronous machine is to be designed to convert its supplied electrical energy into mechanical energy, thereby generating at the drive wheels a propulsion of the vehicle causing torque. For this purpose, the energy supply unit is designed as a high-voltage energy supply unit. The high-voltage energy supply unit is preferably a high-voltage storage device which has a multiplicity of memory modules, each of which is constructed from a plurality of energy storage cells, preferably Li-ion energy storage cells. In this embodiment, the synchronous machine has the function of a traction machine. In the normal operating state, depending on the default value, which is a torque request, the torque current command value and the field current command value are determined such that the torque generated by the synchronous machine at the drive wheels causes propulsion corresponding to the torque request. The torque request can be predetermined by the driver of the vehicle, for example by actuating an accelerator pedal, or by a suitably designed control system, for example a yaw rate control, generally known as an ESP system. In the heating mode state, on the other hand, a time-varying value is preset for the torque current setpoint and a value constant over time for the field current setpoint, in such a way that an energization of the stator windings occurs which does not result in any torque perceptible to the driver of the vehicle or in which the driver of the vehicle perceives no torque. This means that the rotor of the synchronous machine with respect to a rotor position, which is present at the beginning of the Heizbetriebszustands, can perform a so-called micro-stuttering, which leads to no torque on the drive wheels. Micro stuttering is primarily due to the time-varying current-forming current. The rotor of the synchronous machine performs only a negligible and thus imperceptible pendulum motion around a reference position around. In the heating mode, the torque current command value and the field current command value are selected such that a current flows in the stator windings, which generates a loss of heat in them, without, however, generating a noticeable torque on the drive wheels.

If the synchronous machine is a traction machine, then a normal operating state of the synchronous machine is present when the vehicle is operated in a vehicle normal operating state.

Preferably, the synchronous machine should be a permanent-magnet synchronous machine. A synchronous machine designed in this way has the advantage that, in comparison to a current-excited synchronous machine, it has a much simpler design. In the case of a permanently excited synchronous machine, the temporally constant value for the field current nominal value is preferably predetermined such that no damage occurs when the synchronous machine is activated in the heating operating state on the stator windings and on the permanent magnets arranged in the rotor.

It should be noted that the express reference to a traction or prime mover is not intended to be limiting. For example, the inventive Control device also be used in connection with a starter machine, which is adapted to start an internal combustion engine contained in the vehicle. Preferably, however, the drive device according to the invention should be used in conjunction with a traction machine, since a traction machine is dimensioned much larger compared to a starter machine or other electric machine and thus a larger amount of heat loss can be generated.

In a preferred embodiment of the invention, the desired value unit is set up in the heating operating state for the torque current setpoint to predetermine the time-varying value in such a way that a time-varying value course is established for the torque current setpoint. This measure results in a simple control pattern in which it is ensured at the same time that, despite energization of the stator windings on the drive wheels, no noticeable or perceptible torque for the driver arises.

Preferably, an oscillating or pulsating value course should result. Particularly preferably, the torque current setpoint should have an oscillating value profile. Advantageously, a value course is selected which has a sufficiently high frequency with respect to the inertia of the vehicle, so that due to the activation of the synchronous machine in the heating operating state, only a micro-stuttering of the vehicle that is not perceptible or perceptible to the driver occurs. In particular, it should be avoided that the vehicle starts or starts or noticeably sets in motion.

In an advantageous embodiment of the aforementioned measure, the setpoint unit is set up to preset the time-varying value for the torque current setpoint and the constant value for the field current setpoint in such a way that an effective value that results for the time-repeating value course essentially corresponds to constant value of the field current setpoint. This measure ensures that the same current heat losses occur in all three stator windings. For the three stator winding currents, which respectively flow through one of the stator windings, the ratio of the associated current amplitudes is selected such that a uniform distribution of the current heat losses results for the stator windings and thus the synchronous machine. Preferably, the effective value and the constant value of the field current setpoint are equal.

In a preferred embodiment of the invention, the setpoint unit is set up to predetermine the time-constant value as a function of a synchronous machine variable representing the structure and / or operation of the synchronous machine in the heating operating state for the field current setpoint. By this measure, it is possible to optimally adapt the stator winding currents, which flow through the stator windings for generating the current heat losses, to the conditions of the synchronous machine. This can be ruled out to a very high degree that a noticeable or perceptible to the driver torque on the drive wheels.

Preferably, a permanent-magnet synchronous machine is used as the synchronous machine. In such a synchronous machine, the rotor has a plurality of permanent magnets, wherein in the considered machine, the permanent magnets should preferably be arranged such that this results in a reluctance torque. In this case, the setpoint unit is to be set up to predetermine a compensation value in the heating operating state for the field current setpoint as a value that is constant over time, which results in that the reluctance torque is substantially compensated. In this measure, the temporally constant value for the field current setpoint is predetermined in such a way that due to the energization of the stator windings, which results from the torque-forming current and the field-forming current, a main torque is established which has a value which substantially corresponds to the reluctance torque. Preferably, the value of the main torque is equal to the value of the reluctance torque. Thus, it is achieved that the main torque and the reluctance torque are substantially or completely compensated. This procedure ensures to a particular extent that in the heating operating state the driver does not perceive or sense any torque despite the deliberately induced generation of current heat losses. To form a reluctance torque, the permanent magnets are not disposed on the surface of the rotor, but in its interior.

In order to achieve the desired compensation of the reluctance torque, the compensation value is preferably a positive value. Advantageously, the positive value is predetermined in such a way that the reluctance torque and the main torque that occurs due to the permanent magnets essentially and independently compensate for the value predetermined for the torque-generating current. This ensures that despite high currents flowing through the stator windings almost no torque is generated at the drive wheels. This increases the reliability and also reduces vibration or noise.

In a preferred embodiment of the aforementioned measure, the setpoint unit is set up to predetermine the compensation value as a function of at least one operating variable of the synchronous machine. Here, different approaches are conceivable. In a first approach, a plurality of compensation values are stored in the setpoint unit, for example in the form of a lookup table. Depending on at least one operating variable, which is preferably continuously determined during operation of the synchronous machine and which represents or characterizes the operation of the synchronous machine, the most suitable compensation value can then be read from the lookup table. This approach is characterized by a low expenditure on computing capacity. In this approach, the individual compensation values are determined in advance, for example in the context of an application and stored, for example, in a storage medium contained in the setpoint unit, wherein for each compensation value that operating variable or those operating variables for which or from which it was calculated, with deposited are quasi as attributes on the basis of which the compensation value can be read out of the lookup table, which is best suited for the respective operating state of the synchronous machine, which is characterized by occurring operating variables. In a second approach, a calculation rule, preferably in the form of a model, can be stored in the setpoint unit with which the compensation value is calculated during operation of the synchronous machine, specifically as a function of the at least one operating variable currently required for this and occurring during operation of the synchronous machine , A third approach is also conceivable, based on a combination of lookup table and model.

gegeben, die sich aus der Drehmomentgleichung M = m / 2p[(L_d – L_q)I_d + Ψ_PM]I_q für die Vorgabe ergibt, dass das Reluktanzdrehmoment (L_d – L_q)I_dI_q gleich dem Hauptdrehmoment Ψ_PMI_q ist. Die in der Drehmomentgleichung verwendeten Größen haben folgende Bedeutung: m entspricht der Anzahl der Statorphasen bzw. Statorstränge; p entspricht der Polpaarzahl; L_d entspricht der Statorinduktivität in Richtung der d-Achse des rotorfesten Koordinatensystems; L_q entspricht der Statorinduktivität in Richtung der q-Achse des rotorfesten Koordinatensystems; I_d entspricht dem feldbildenden Strom; I_q entspricht dem drehmomentbildenden Strom; Ψ_PM entspricht dem durch die Permanentmagnete bewirkten magnetischen Fluss.In a permanent magnet synchronous machine having a reluctance torque due to the arrangement of the permanent magnets in the rotor, said compensation value is by the relationship

given, resulting from the torque equation M = m / 2p [(L _d -L _q ) I _d + Ψ _PM ] I _q for the specification, the reluctance torque (L _d -L _q ) I _d I _{q is} equal to the main torque Ψ _PM I _q . The variables used in the torque equation have the following meaning: m corresponds to the number of stator phases or stator strings; p corresponds to the pole pair number; L _d corresponds to the stator inductance in the direction of the d-axis of the rotor-fixed coordinate system; L _q corresponds to the stator inductance in the direction of the q-axis of the rotor-fixed coordinate system; I _d corresponds to the field-forming current; I _q corresponds to the torque-forming current; Ψ _PM corresponds to the magnetic flux caused by the permanent magnets.

The quantities which are contained in the relationship for the determination of the compensation value can each be represented or determined individually according to a respectively associated calculation rule from the following variables: the field-forming current I _d , the torque-forming current I _q and the temperature T _PM permanent magnets. The temperature T _{PM of} the permanent magnets can be detected, for example, by means of a number of temperature sensors which are arranged on or in the immediate vicinity of individual permanent magnets. Alternatively, this temperature can also be determined by means of a mathematical model or observer, starting from the electrical losses determined for the synchronous machine, taking into account a thermal contact resistance determined in advance with respect to the permanent magnets.

Consequently, the drive device further includes an evaluation unit, which is set up to at least determine whether a heating operating state exists. For this purpose, the evaluation are fed different sizes. On the one hand, these are quantities by means of which it can be determined whether there is any need for heating, ie whether there is a need to control the synchronous machine in such a way that current heat losses occur and thus a loss of heat is generated. These variables may be, for example, an interior temperature value T _I that represents the temperature of the vehicle interior and / or an ambient temperature variable T _U that represents the temperature of the vehicle environment. On the other hand, these are quantities on the basis of which it can be determined whether the synchronous machine is in an operating state or engine operating state which allows said drive. For this purpose, it may be provided, for example, to supply the evaluation unit with a rotor speed variable detected by means of a suitable speed sensor. In addition, it can also be provided that quantities are evaluated by means of which it can be determined whether the vehicle is in such a vehicle operating state that permits the control of the synchronous machine to be carried out in a heating operating state. First and foremost, it is a question of determining whether the vehicle is stationary, ie whether the vehicle operating state vehicle standstill exists. Thus, a standstill detection is performed. For this purpose, the evaluation unit, for example, those for the preferably four vehicle wheels be determined with the help of suitable Raddrezahlsensoren respectively determined wheel speeds. Alternatively or additionally, the evaluation unit can also be supplied with a vehicle speed variable representing the speed of the vehicle.

In a further preferred embodiment of the invention, the evaluation unit is further configured to perform a monitoring of the vehicle and / or the synchronous machine during the heating operating state. With this measure, it can be ensured that no torque that is perceptible or perceptible to the driver is generated during the activation of the synchronous machine that takes place in the heating operating state. In order to be able to carry out the monitoring, the evaluation unit may, for example, be supplied with a rotor speed variable detected by means of a suitable speed sensor and / or with a rotor position variable detected by means of a suitable angle sensor. These two quantities are best suited to determine whether the driving produces a disturbing torque that causes an undesirable propulsion of the vehicle, as they directly detect or reproduce the rotor reaction. Alternatively or additionally, the evaluation unit can also be supplied with the wheel speeds determined for the vehicle wheels and / or a vehicle speed variable. Overall, it must be ensured that the vehicle does not start due to the activation of the synchronous machine taking place in the heating operating state. The goal of this monitoring is to determine if the torque-forming current is properly adjusted, i. H. whether the torque current setpoint is specified appropriately. If, for example, it is determined during monitoring that the rotor speed has a value other than zero and / or that the rotor position variable changes over time and / or that at least one of the wheel speeds has a value other than zero and / or the vehicle speed variable has a value other than zero has, then this is a sign that the torque-forming current is not adjusted properly. In this case, the torque-forming current can be tracked by a corresponding specification of a matched or modified torque current setpoint. Alternatively, the driving of the synchronous machine in the heating operation state may be terminated.

In an advantageous embodiment of the invention can also be provided that the taking place in the heating mode energization of the synchronous machine can also be used to heat the vehicle interior before driving start, so that the driver rises when driving in a warm vehicle. For this purpose, an additional triggering condition would have to be examined, as is the case, for example, with auxiliary heaters. For example, the driver could specify a time at which he would like to start a journey, and in dependence of which the heating of the vehicle interior takes place by means of the current supply of the synchronous machine taking place in the heating operating state.

Preferably, the temporally constant value for the field current setpoint is predetermined so that no damage occurs in the control of the synchronous machine in the heating mode to the permanent magnet of the rotor or to the field winding of the rotor.

As can be seen from the above statements, the evaluation unit is supplied with different sizes and then evaluated in this.

Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description. Show it:

1 a schematic representation of a hybrid vehicle equipped with the invention,

2 a schematic representation for explaining the structure of the inventive driving device and running in this process according to the invention, and

3 in the form of a time chart, the course of the phase currents flowing through the stator windings during the heating operating state.

1 shows a vehicle constructed as a hybrid vehicle 10 , which is designed as a parallel hybrid vehicle, preferably with the functionality of a plug-in hybrid. That the following statements are made in connection with a hybrid vehicle should not have any restrictive effect. Of course, the concept according to the invention can also be used in an electric vehicle or in a vehicle equipped only with an internal combustion engine.

The vehicle 10 has drive wheels 12 and non-powered wheels 14 on. The vehicle 10 has an electric machine that as a synchronous machine 16 is formed and which has a gearbox 18 and a differential 20 technically with the drive wheels 12 connected is. The synchronous machine 16 can be permanent-energized or energized. Preferably, it should be a permanent magnet synchronous machine 16 act, which should have a reluctance due to the arrangement of permanent magnets in the rotor and thus a reluctance during operation. The synchronous machine 16 is via one of a drive device 22 controllable inverter 24 connectable to an energy supply unit, wherein the energy supply unit as Hochvoltenergiebereitstellungseinheit 26 is trained. The inverter 24 has a plurality of inverter switches arranged to a full bridge designed for three-phase operation. The inverter switches may be, for example, MOSFET transistors or IGBTs.

As the illustration in 1 is the high-voltage energy supply unit 26 constructed from a variety of energy supply modules, one of which is exemplified by the reference numeral 28 is marked. The energy supply module 28 in turn is constructed from a plurality of energy supply cells, one of which is exemplified by the reference numeral 30 is marked. With a block 32 is hinted that in the high-voltage energy supply unit 26 in addition to the components required for the storage of electrical energy further components required for the realization of control and / or monitoring functionalities are included. So it may be at the block 32 to act a parent monitoring and / or control unit, for example, a so-called SME unit act.

The synchronous machine 16 is trained to receive her from the High Voltage Energy Provisioning Unit 26 to convert supplied electrical energy into mechanical energy, thereby at the drive wheels 12 a propulsion of the vehicle 10 To generate acting torque.

In addition to the synchronous machine 16 has the vehicle 10 via an internal combustion engine 34 that has a clutch 36 and the gearbox 18 as well as the differential 20 the drive wheels 12 of the vehicle 10 can drive. The drive wheels 12 can do this alone by the synchronous machine 16 or by the internal combustion engine alone 34 or be driven in combination by both.

2 shows a schematic representation for explaining the structure of the inventive driving device 22 and in this proceeding inventive method. It is a permanent magnet synchronous machine 16 shown a housing 38 has and arranged therein a stator 40 and a rotor 42 , The stator has stator windings, one of which is denoted by the reference numeral 44 is marked. The rotor 42 has a plurality of permanent magnets 46 on, for reasons of clarity in 2 only one is shown. The permanent magnets 46 should do so in the rotor 42 be arranged, thereby creating a reluctance effect and during operation of the synchronous machine 16 gives a reluctance torque. As the illustration in 2 can be seen, it should be a three-phase, permanent magnet synchronous machine 16 act. The representation of a permanent-magnet synchronous machine should have no limiting effect, of course, the inventive approach can also be used in a current-excited synchronous machine.

As already stated, the synchronous machine is 16 via an inverter 24 with a high-voltage energy supply unit 26 connectable. This is the drive device 22 set up to control signals A _S1 , A _S2 , A _S3 for controlling the inverter 24 provide. For this purpose, the drive device 22 a setpoint unit 48 and a conversion unit 50 on. Furthermore, the drive device 22 an evaluation unit 52 on.

The setpoint unit 48 is adapted in a normal operating state in accordance with a field oriented control approach in dependence on a preset value M _to a torque current command value I _qS for a torque-forming current I _q and a field current target value to determine I _DS for a field-forming current I _d, and in a direction different from the normal operating state of heating operation for the torque _{current setpoint} I _qS a time-changing value and for the field current setpoint I _{dS to} specify a time-constant value. The conversion unit 50 is configured to determine the drive signals A _S1 , A _S2 , A _S3 as a function of the torque _{current setpoint value} I _qS and of the field current setpoint value I _dS .

The default value M _soll is the drive unit 22 , more precisely, the setpoint unit 48 starting from a standard value unit 54 fed. The default value M _soll may be a setpoint torque that may correspond to a driver request that the driver of the vehicle 10 by corresponding operation of an accelerator pedal (not shown), or correspond to a system default, which is determined by a contained in the vehicle (also not shown) slip control unit, this unit may be, for example, a traction control unit or a yaw rate control unit. The default value M _soll can also be formed as a combination of both specifications.

In a normal operation state, the torque _{current command value} I _qS and the field current command value I _{dS become} in the command value unit 48 determined according to a field-oriented control approach. The two current setpoints I _dS and I _qS relate to this by means of the stator windings 44 generated stator magnetic field, which is a rotating magnetic field. The determination of these two setpoints is the approach a so-called field-oriented control or vector control. In this approach, the stator-related three-phase coordinate system is mapped to a rotor-related two-phase coordinate system in a three-phase synchronous machine. In this coordinate system, I _dS corresponds to the setpoint value for the field-forming current component I _d and I _qS corresponds to the setpoint value for the torque- _forming current component I _q . The two current components I _d and I _q represent operating variables of the synchronous machine. In one of the setpoint unit 48 downstream conversion unit 50 are generated from the two current setpoints I _dS , I _qS control _signals A _S1 , A _S2 , A _S3 , which is an inverter 24 be supplied. The inverter 24 has a plurality of inverter switches arranged to a full bridge designed for three-phase operation. The inverter switches may be, for example, MOSFET transistors or IGBTs. According to the drive signals A _S1 , A _S2 , A _S3 , the individual stator windings 44 with a high-voltage energy supply unit 26 connected, so that at the individual stator windings 44 set the phase voltages U _P1 , U _P2 , U _P3 .

The drive device 22 is set up to _preset a time-varying value in a heating _{operating state} that differs from the normal _{operating state} for the torque _setpoint I _{qS, and} a value that is constant in time for the field current setpoint I _dS . This ensures that through the stator windings 44 Phase currents flow in the stator windings 44 lead to current heat losses, so that on the synchronous machine 16 A loss of heat is created, which is used to heat the interior of the vehicle 10 can be used without causing a noticeable or perceptible to the driver torque by the synchronous machine 16 is produced.

The setpoint unit 48 is set up in the heating _{operating state to} specify the time-varying value in such a way that a time-varying course of values is thereby established for the torque _{current setpoint} I _qS . Next, the setpoint unit 48 be set up for the torque _{current setpoint} I _qS the time-varying value and for the field current setpoint I _dS the temporally constant value such that an effective value, which results for the time-repeating value curve substantially corresponds to the constant value of the field current setpoint las ,

In an advantageous embodiment, the setpoint unit 48 be set up in the heating mode for the field current setpoint I _dS the time constant value as a function of a structure and / or operation of the synchronous machine 16 pretending to represent synchronous machine size. This is particularly advantageous when it comes to a permanent-magnet synchronous machine 16 acts, in which the permanent magnets 46 are arranged such that this results in a reluctance torque. In this case, it can be provided that the setpoint unit 48 for the field current setpoint I _dS as a value constant over time, a compensation value I _dK that results in that the reluctance _{torque is} substantially compensated. It can be provided, the compensation _value I _dK in response to at least one operating _{variable of} the synchronous _machine 16 pretend. As in 2 indicated, this can be the setpoint unit 48 different sizes G _n starting from the conversion unit 50 be supplied. The quantities G _n may be, on the one hand, quantities that are in the conversion unit 50 be determined by yourself. For example, it may be a current value for the torque-forming current I _q and the field-forming current I _d currently determined during operation of the synchronous machine or of the vehicle. Both actual values are in the conversion unit 50 present, since starting from the two setpoint values torque _current setpoint I _qS and field current setpoint I _dS and these two actual values control deviations are determined on the basis of which the control signals A _S1 , A _S2 , A _{S3 are} determined. On the other hand, they can be quantities, that of the conversion unit 50 even needed for the tasks to be performed in it. Such sizes can the conversion unit 50 as if by an arrow 56 indicated, starting from the evaluation unit 52 be supplied, or as indicated by an arrow 58 indicated, starting from different in the vehicle 10 arranged sensors 60 be supplied.

The drive device 22 also contains an evaluation unit 52 , The evaluation unit 52 On the one hand, it is set up to determine whether a heating operating state exists, the result of the setpoint unit 48 by means of a logical variable H is supplied. In this context, the evaluation unit 52 supplied to different sizes and evaluated in this, for example, starting from a Innenraumtemperaursensor 62 a passenger compartment temperature value T _I representing the temperature of the vehicle interior and / or starting from an ambient temperature sensor 64 an ambient temperature variable T _U representing the temperature of the vehicle environment and / or starting from a rotor speed sensor 66 a rotor speed size n _red and / or based on wheel speed sensors 68 Raddrehungsgrößen n _ij and / or starting from a corresponding determination unit 70 a vehicle speed _quantity v _f .

On the other hand, the evaluation unit 52 configured to monitor the vehicle during the heating mode 10 and / or the synchronous machine 16 perform the result of the setpoint unit by means of a logical variable K is supplied. In this connection, in the evaluation unit 52 different sizes are evaluated, for example one with a rotor angle sensor 72 detected rotor position size δ _red and / or the rotor speed size n _red and / or the wheel speed n _ij and / or the vehicle speed variable v _f .

3 shows for a three-phase synchronous machine in the form of a time chart, the course of the during the Heizbetriebszustands flowing through the stator windings phase currents. The course of the phase currents shown is characteristic of the approach according to the invention, in the presence of a heating operating state for the torque current setpoint, a time-varying value, in particular an oscillating value, and to specify a time-constant value for the field current setpoint. In other words, if the two current setpoints are specified in this form, the three phase currents in the case of a three-phase synchronous machine have the in 3 shown course. In the illustrated case, the amplitudes of the phase currents are such that substantially the same electrical losses occur in the three stator windings, so that a uniform heating for the synchronous machine is provided. This amplitude _{constellation} is achieved by _{predetermining} the time-varying value for the torque _{current setpoint} I _qS and the temporally constant value for the field current setpoint I _{dS in} such a way that the effective value which is responsible for the time-repeating value _{profile of} the torque _{current setpoint} I _qS or torque-forming current substantially corresponds to the constant value of the field current setpoint I _dS .

According to the invention, a synchronous machine installed in a vehicle is controlled in a heating operating state in such a way that it generates a waste heat without generating a torque in the mean value and thus causing a propulsion of the vehicle. For this purpose, based on a field-oriented control approach or a vector-based control for the individual stator windings of the synchronous machine, the respective currents flowing through them, the phase currents are set according to the invention.

The focus of the drive device or the method according to the invention is directed to the heating of the vehicle interior. However, this should not have any limiting effect. Of course, both can also be used in a completely different direction, for example to heat any component installed in the vehicle.

For reasons of clarity, it has been dispensed with in the described figures to represent those components which are required for the removal or supply of the heat loss from the synchronous machine to the object to be heated, preferably the interior of the vehicle.

It has been stated on various occasions that in the heating mode for the torque current setpoint, a time-varying value and for the field current setpoint a time-constant value are set such that due to the resulting energization of the stator windings, no torque that can be felt by the driver of the vehicle occurs or in which the driver of the vehicle perceives no torque. By this referring to the driver explanation shall only be expressed that the procedure according to the invention is basically designed so that a driver sitting in the vehicle undergoes no noticeable or perceptible impairment by an energizing of the stator windings taking place in the heating operating state during this time. It should be expressly pointed out that a heating of the vehicle interior which takes place in accordance with the inventive approach can also take place when there is no person in the vehicle interior or before the driver takes his seat in the vehicle. In other words, with the approach according to the invention also a heating of the vehicle interior should be possible, as it is possible with a classic heater or is known from this, namely, in time before the driver takes a seat in the vehicle.

Finally, the following is explained: it is stated above that in the heating operating state for the torque current setpoint, a time-varying value and for the field current setpoint, a temporally constant value is specified. This should be understood in such a way that these values, in particular the temporally constant value for the field current value, are given basically as such. However, due to the physical effects prevailing in the synchronous machine, in particular with regard to the temporally constant value specified for the field current setpoint, a slight or negligible deviation may occur, in any case not deliberately predetermined deviation. In particular, the field current setpoint or the resultant field-forming current can show slight pulsation due to saturation effects, which is much lower compared to the time-varying value that is intentionally set for the torque current setpoint and is therefore to be regarded as negligible.

LIST OF REFERENCE NUMBERS

10

vehicle

12

drive wheels

14

non-powered wheels

16

synchronous machine

18

transmission

20

differential

22

driving

24

inverter

26

High-voltage power supply unit

28

Energy supply module

30

Energy supply cell

32

block

34

internal combustion engine

36

clutch

38

casing

40

stator

42

rotor

44

stator

46

permanent magnet

48

Reference unit

50

conversion unit

52

evaluation

54

Default Value Unit

56

arrow

58

arrow

60

sensors

62

Innenraumtemperaursensor

64

Umgebungstemperaursensor

66

Rotor speed sensor

68

wheel speed sensors

70

determining unit

72

Rotor angle sensor

Claims (10)

Drive device for a synchronous machine arranged in a vehicle, wherein the synchronous machine has a rotor and a stator, wherein the vehicle further comprises an energy supply unit and an inverter, wherein the synchronous machine is connectable to the energy supply unit via the inverter, the drive device being adapted therefor, To provide drive signals for driving the inverter, and having for this purpose a setpoint unit and a conversion unit, wherein the setpoint unit is configured, in a normal operating state according to a field-oriented control approach in response to a default value, a torque current setpoint for a torque-generating current and a field current setpoint for a field-forming current to determine, and in a different from the normal operating state heating mode for the torque current setpoint a temporally än the value and for the field current setpoint to specify a time-constant value, and wherein the conversion unit is configured to determine the drive signals in dependence on the torque current setpoint and the field current setpoint value. Control device according to claim 1, characterized in that the vehicle further comprises drive wheels and the energy supply unit is a high voltage energy supply unit, wherein the synchronous machine is adapted to convert their supplied from the high voltage energy supply unit electrical energy into mechanical energy, thereby to the drive wheels to generate a propulsion of the vehicle causing torque. Drive device according to one of the preceding claims, characterized in that the setpoint unit is adapted to specify in the heating mode for the torque flow setpoint the time-varying value such that thereby sets a time-repeating course of values for the torque flow setpoint. Control device according to claim 3, characterized in that the setpoint unit is adapted to predetermine the time-varying value for the torque current setpoint and the time-constant value for the field current setpoint such that an effective value which results for the time-repeating value course substantially corresponds to the constant value of the field current setpoint. Drive device according to one of the preceding claims, characterized in that the setpoint unit is adapted to specify in the heating operation state for the field current setpoint the time constant value as a function of the construction and / or operation of the synchronous machine representing synchronous machine size. Drive device according to one of the preceding claims, characterized in that it is a permanent-magnet synchronous machine in which the rotor has a plurality of permanent magnets, wherein the permanent magnets are arranged such that thereby results in a reluctance torque, wherein the setpoint unit is adapted to in the heating mode for the field current setpoint as a time constant value, a compensation value that results in that the reluctance torque is substantially compensated. Control device according to claim 6, characterized in that the setpoint unit is adapted to the compensation value in dependence pretend at least one operating variable of the synchronous machine. Drive device according to one of the preceding claims, characterized in that the drive device further includes an evaluation unit which is adapted to at least determine whether a heating operation state is present. Drive device according to one of the preceding claims, characterized in that the evaluation unit is further adapted to perform a monitoring of the vehicle and / or the synchronous machine during the heating operating state. A method for driving a vehicle-mounted synchronous machine, wherein the synchronous machine comprises a rotor and a stator, the vehicle further comprising an energy supply unit and an inverter, wherein the synchronous machine is connected by appropriately driving the inverter via this with the energy supply unit, with the following in a drive device running steps: Determining a torque current command value for a torque-forming current and a field current command value for a field-forming current as a function of a default value in a normal operating state according to a field-oriented control approach, and setting a time-varying value for the torque current command value and a time-constant value for the field current command value in a of the Normal operating state different heating mode, Determining drive signals as a function of the torque current setpoint and the field current setpoint, and - Providing the drive signals for driving the inverter.

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