DE102020207122A1 - Arrangement and method for controlling an electric motor for a vehicle steering system - Google Patents

Abstract

An arrangement or a method for controlling an electric motor for vehicle steering is proposed. Two driver circuits designed to be redundant to one another are provided for generating driver currents for energizing coils of the electric motor. Furthermore, a configurator is used which is connected to the driver circuits for receiving the driver currents and which assigns the respective control currents to the respective coils as a function of a signal. A control module generates the signal by means of at least one lookup table, the control module using different measured values for this on the driver circuits and / or on the configurator and / or on the electric motor.

Description

The invention relates to an arrangement and a method for controlling an electric motor for a vehicle steering system according to the preamble of the independent claims.

Out EP 3 113 355 B1 a motor control device, an electric power steering device and a vehicle having this motor control device are known. An electric motor in a star connection is controlled by two redundant inverter circuits. The driver currents are released by electronic switches. A so-called abnormality detector is provided, which switches off in the event of a short circuit of field effect transistors of the respective inverter. This is also recognized when the transistors are idle.

The arrangement according to the invention and the method according to the invention for controlling an electric motor for a vehicle steering system with the features of the independent claims have the advantage that the control is now determined via a so-called lookup table. This activation relates to a configurator which is connected to the driver circuit for receiving the driver currents and which assigns the respective activation currents to the respective coils of the electric motor as a function of a signal. With the lookup table, it is possible to determine the appropriate energization of the respective coils and from which driver circuit this is to be carried out as a function of various measured values on the driver circuits and / or the configurator and / or the electric motor. Overall, this enables better adaptation to the event of an error. This makes it possible, in particular, to logically compensate for the failure of a coil or a driver circuit by still functioning coils or driver circuits then compensating for this failure, for example, by applying a higher current. This leads to a lighter electric motor, since structural redundancy of the coils is no longer necessary.

• - Zwei zueinander redundant ausgeführte Treiberschaltungen zur Erzeugung von Treiberströmen für eine Bestromung von Spulen des Elektromotors,
• - einem Konfigurator, der mit den Treiberschaltungen zur Aufnahme der Treiberströme verbunden ist und der in Abhängigkeit von einem Signal die jeweiligen Ansteuerströme den jeweiligen Spulen zuordnet,
• - einem Steuerbaustein, der das Signal mittels wenigstens einem Lookup-Table erzeugt, wobei der Steuerbaustein dafür verschiedene Messwerte an den Treiberschaltungen und/oder dem Konfigurator und/oder an dem Elektromotor verwendet.

Therefore, an arrangement for controlling an electric motor for a vehicle steering system with the following features is proposed:

• - Two mutually redundant driver circuits for generating driver currents for energizing coils of the electric motor,
• - a configurator which is connected to the driver circuits for receiving the driver currents and which assigns the respective control currents to the respective coils as a function of a signal,
• a control module which generates the signal by means of at least one lookup table, the control module using different measured values for this on the driver circuits and / or the configurator and / or on the electric motor.

• - Erzeugen von Treiberströmen für eine Bestromung für jeweiligen Spulen des Elektromotors mit zwei zueinander redundant ausgeführten Treiberschaltungen.
• - Aufnahme der Treiberströme durch einen mit den Treiberschaltungen verbundenen Konfigurator.
• - Zuordnen der Treiberströme durch den Konfigurator zu den jeweiligen Spulen in Abhängigkeit von einem Signal.
• - Erzeugen des Signals durch einen Steuerbaustein unter Verwendung wenigstens eines Lookup-Tables, wobei der Steuerbaustein dafür verschiedene Messwerte an den Treiberschaltungen und/oder dem Konfigurator und/oder dem Elektromotor verwendet.

Furthermore, a method for controlling an electric motor for a vehicle steering system with the following method steps is proposed:

• - Generating driver currents for energizing the respective coils of the electric motor with two driver circuits that are redundant to one another.
• - Recording of the driver currents by a configurator connected to the driver circuits.
• - Assignment of the driver currents by the configurator to the respective coils depending on a signal.
• Generation of the signal by a control module using at least one lookup table, the control module using different measured values for this on the driver circuits and / or the configurator and / or the electric motor.

In the present case, the arrangement for controlling an electric motor is to be understood as a circuit that energizes the electric motor according to the invention. This energization takes place in such a way that the electric motor is driven as intended for the vehicle steering. Vehicle steering can be understood to mean a front-axle or rear-axle steering or a combination thereof.

Activation is accordingly to be understood as meaning, in particular, the energization of the coils of the electric motor. The electric motor can be a DC or AC motor. A permanently excited electric motor can be used for this. An electric motor has a stator and a rotor and the rotor is set in motion by energizing the coils on the stator. The rotor can in particular have magnets. Vehicle steering is a deliberate change in the direction of travel as a function of a driver's request or an automatic function that changes the direction of travel as a function of parameters. This also includes, for example, automated fallback functions.

In the present case, the driver circuits include a circuit for reducing electromagnetic interference, a circuit for stabilizing the voltage and output stages. The redundant design means that the driver circuit works twice is available. The driver currents are output by the driver circuits and ultimately switched through to the electric motor by the configurator in order to energize the corresponding coils as intended.

In the present case, the configurator is a circuit for receiving the driver currents and which then assigns the trigger currents to the respective coils depending on the signal from the driver currents, so that the trigger currents, which can be identical to the driver currents, energize the respective coils. If this is done in certain temporal dependencies, the electromagnetic field migrates in the coils and attracts the rotor to rotate.

A control module can be understood to mean, for example, a microcontroller. The signal that the control module outputs to the configurator can be used there accordingly in a direct control for the individual electronic switches in the configurator. The configurator can have signal processing for this purpose. However, it can also be provided that the individual electronic switches in the configurator are controlled directly by the control module via individual lines. The control module determines the signal using at least one lookup table. Lookup table can be a multidimensional table in which the signal that is to be output for these measured values is specified by various measured values. I. E. the measured values generate scenarios which then lead to corresponding signals.

The measures and developments listed in the dependent claims make it possible to improve the arrangement specified in the independent claims or the method specified in the independent claims for controlling an electric motor for a vehicle steering system.

It is provided, for example, that the various measured values from the at least one lookup table load a scenario that defines the signal. In this way, it can be determined in a preliminary phase or development phase under which conditions which control currents flow to the coils and thus a suitable current can be supplied very quickly, especially in the event of a fault, e.g. when a coil has a short circuit or an open circuit. The term scenario defines various situations that are determined by the measured values.

It is also proposed that the configurator has several electronic switches that are controlled as a function of the signal. The configurator can be a semiconductor module on which the electronic switches with the transistors are arranged. However, it could also consist of discrete building blocks or a mixture of integrated circuits and discrete building blocks.

In addition, it is provided that the measured values are at least one phase angle and / or at least one current value and / or at least one voltage value and / or at least one temperature value and / or at least one magnetic field value. With these electrical parameters, it is possible to draw accurate conclusions about the functionality of the driver circuits of the configurator and the electric motor. This also includes the speed of the electric motor or a direction of rotation of the electric motor.

It is also proposed that only one coil is provided for a respective stator.

In addition, it is proposed that the respective coil be energized in each case as a function of the signal. As a robustness measure, two coils, which are operated by different power units, are usually wound onto a stator slot. If an electronic unit or a coil fails, the intact electronic unit or the intact coil takes over the work. This has the advantage that, even in the event of a fault, the geometric arrangement remains unchanged and an additional stator slot can be dispensed with. On the other hand, however, the present invention differs: each individual slot does not have to be provided with twice the number of coils (i.e. twice the weight of the coils (copper is relatively heavy with a density of 8.92 g / cm ³ ), but we can have one Rotational movement can still be guaranteed even with a failed power electronics or coil without having to double the number of coils. The system is logically reconfigured in response to such a failure. The motor can thus be made more compact and it is lighter.

It is also proposed that the respective driver circuit have a respective circuit for reducing electromagnetic interference, a respective voltage conditioning and a respective output stage. The circuit for reducing electromagnetic interference reduces external electromagnetic interference. The tension conditioning stabilizes the tension values to certain values. I. E. these values are not exceeded or undercut. The driver currents are generated by the output stage.

Exemplary embodiments of the invention are shown in the drawing and are explained in more detail in the description below.

• 1 ein erstes Blockschaltbild für eine Ansteuerung einer Fahrzeuglenkung;
• 2 ein Blockschaltbild der erfindungsgemäßen Anordnung;
• 3 eine Darstellung des Konfigurators;
• 4 eine zweite Darstellung des Konfigurators;
• 5 eine vereinfachte Darstellung des Elektromotors und
• 6 ein Flussdiagramm des erfindungsgemäßen Verfahrens.

Show it

• 1 a first block diagram for controlling a vehicle steering system;
• 2 a block diagram of the arrangement according to the invention;
• 3 a representation of the configurator;
• 4th a second representation of the configurator;
• 5 a simplified representation of the electric motor and
• 6th a flow chart of the method according to the invention.

1 shows in a block diagram the arrangement according to the invention for controlling a vehicle steering system in the vehicle. Here, in a simplified manner, only one axle with connected wheels is shown, which is controlled by a steering LI being affected. An electric motor EM moves the steering LI so that the direction of travel changes according to the driver's request or an automated function. The electric motor EM is controlled by a control A. controlled with regard to direction of rotation, speed and other parameters. Via a so-called human-machine interface HM is the control A. controlled and this causes it to execute the specified function according to the driver's request.

In 2 the arrangement according to the invention is described in detail in a block diagram. A control module SOC receives measured values from the output stages ES1 and ES2 as well as from the configurator Theatrical Version as well as from the electric motor EM . The control module SOC controls the configurator Theatrical Version with the signal. This then does what the electric motor does EM is energized. There are two driver circuits for the power supply LE1 and LE2 before. These driver circuits essentially consist of a circuit for reducing electromagnetic interference EMC1 and EMC2 , a stress conditioning SK1 and SK2 as well as a respective power amplifier ES1 and ES2 . The power amplifiers ES1 and ES2 send the driver currents to the configurator Theatrical Version from that with its circuit depending on the signal from the control module SOC the control currents for the electric motor EM generated. Thereby give the driver circuits LE1 and LE2 three driver currents each, so that the electric motor is supplied with six control currents. The measuring lines with which the control module SOC Measured values from the driver circuits LE1 and LE2 , the configurator Theatrical Version and the electric motor EM are designated by M1 to M4. The driver circuits ES1 and ES2 Voltage or current values as well as from the configurator Theatrical Version and also from the electric motor EM be transmitted. On the electric motor EM Not only the coils can be monitored, but also the magnetic field, for example via a Hall sensor or the temperature of the electric motor via a temperature sensor EM . It is also possible to sense the speed and the direction of rotation.

3 shows a first embodiment of the configurator in a detail image Theatrical Version . The configurator Theatrical Version with the driver currents 11 to 16 applied. Turns out the switches S1 to S6 for the respective driver currents and these switches S1 to S6 are controlled by the signal. I. E. here the signal can at most say the switches S1 to S6 either to close or to leave open. I. E. the currents 11 to 16 are blocked or allowed through. In this case, however, it is provided that the redundantly designed driver circuits are always used, ie the currents output are always used for energization in the error-free state.

4th shows an alternative. This is where the driver flows through a network of nodes 11 to 16 the control currents I1 * to I6 * educated. In this case, links between these currents are now possible in order, for example, to compensate for a fault in a coil that can no longer be supplied with current by increasing the current supply to another coil. The individual nodes are controlled depending on the signal. The configurator Theatrical Version a signal processing that processes the signal and controls the individual nodes accordingly. The nodes can be one or more transistors. Another fault is a failure of the power electronics or the configurator.

5 shows a simplified representation of the electric motor according to the invention. The coils are lying there A to I before. These coils are on a stator S. attached. There is a rotor in the middle R. that can turn in both directions of rotation.

This direction of rotation depends on the current supply to the coils A to I away. If the magnetic field moves from A to I, the rotor turns R. e.g. clockwise. If one of the coils fails due to idling or a short circuit, or the controlling power electronics fail, this coil is no longer energized and, for example, other coils can be energized more strongly in order to compensate for the failure. Adjacent coils in particular can then take over this higher current supply.

6th shows a flow chart for the method according to the invention. In process step 600 are the drive currents from the two driver circuits LE1 and LE2 generated. These driver currents 11 to 16 are in process step 601 through the configurator Theatrical Version recorded. In process step 602 these driver currents are increasing Control currents assigned. The signal is in process step 603 formed by a lookup table that is based on the measured values 604 is determined. This signal determined by the lookup table becomes the configurator Theatrical Version supplied in order to effect the assignment of the drive currents to drive currents.

List of reference symbols

HM

Human machine interface

A.

Control

EM

Electric motor

LE

steering

R.

wheels

SOC

Control module

EMC1, 2

Circuit to reduce electromagnetic interference

SK1, 2

Stress conditioning

SE1, 2

Power amplifiers

LE1, 2

Driver circuits

M1 to M4

Measurement lines

Theatrical Version

Configurator

11 to 16

Driver currents

S1 to S6

counter

I1 * to I6 *

Control currents

RO

rotor

A to I

Wash

S.

stator

600 to 604

Procedural steps

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 3113355 B1 [0002]

Claims (8)

Arrangement for controlling an electric motor (EM) for a vehicle steering (LE) with: - Two mutually redundant driver circuits (LE1, 2) for generating driver currents (11 to 16) for energizing coils (A to I) of the electric motor (EM); - a configurator (KF) which is connected to the driver circuits for receiving the driver currents (11 to 16) and which assigns the respective control currents (I1 * to I6 *) to the respective coils (A to I) as a function of a signal, - A control module (SOC), which generates the signal by means of at least one lookup table, the control module (SOC) using different measured values for this on the driver circuits and / or on the configurator (KF) and / or on the electric motor (EM). Arrangement according to Claim 1 , characterized in that the various measured values from the at least one lookup table are used to load a scenario which defines the signal. Arrangement according to Claim 1 or 2 , characterized in that the configurator (KF) has several electronic switches (S1 to S6) which are controlled as a function of the signal. Arrangement according to one of the preceding claims, characterized in that the measured values include at least one phase angle and / or at least one current value and / or at least one voltage value and / or at least one temperature value and / or at least one magnetic field value and / or a speed of the electric motor (EM) and / or a direction of rotation of the electric motor (EM). Arrangement according to one of the preceding claims, characterized in that only one coil is provided for a respective stator (S). Arrangement according to one of the preceding claims, characterized in that the respective coil (A to I) is in each case energized as a function of the signal. Arrangement according to one of the preceding claims, characterized in that the respective driver circuit (LE1, 2), a respective circuit for reducing electromagnetic interference (EMV1, 2), a respective voltage conditioning (SK1, 2) and a respective output stage (ES1, 2) having. Process for controlling an electric motor EM for a vehicle steering system (LE) with the following process steps: - Generating driver currents (11, 16) for energizing respective coils (A to I) of the electric motor (EM) with two mutually redundant driver circuits (LE1, LE2). - Recording of the driver currents by a configurator (KF) connected to the driver circuits. - Assignment of the driver currents (11, 16) by the configurator (KF) to the respective coils (A to I) depending on a signal. - Generation of the signal by a control module (SOC) using at least one lookup table, the control module (SOC) for different measurement values on the driver circuits (LE1, LE2) and / or on the configurator (KF) and / or on the electric motor (EM) used.

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