DE102019116516A1 - Method for speed control of a mechanically commutated compressor motor - Google Patents

Abstract

The invention relates to a mechanically commutated brush motor (10) for a compressor device (100) with a compressor (8) for generating compressed air, with a rotor (9) and a stator (11), a current sensor (14) for measuring a motor current (18) and an electronic control and regulating device (12) which has a speed control device (13) for the rotor and a signal input (16) for the motor current (18) measured by the current sensor (14). According to the invention, the speed control device (13) has: a memory (20) in which a calibration characteristic (22) is stored, which indicates a speed (17) determined via a compression stroke (15) of the compressor (8), a calibration module (24) for Determining a calibration speed (26) from the measured motor current (18), the speed (17) determined therefrom being able to be calibrated via the calibration characteristic curve (22) to the compression stroke (15) as the calibration speed (26), and a determination module (28) for determination an operating speed (23), by means of which an average motor current (21) can be determined from the measured motor current (18) during operation, from which the operating speed (23) can be determined, and a comparison module (30) for comparison (32) between the operating speed ( 23) and the calibration speed (26), and a control module (34) by means of which the motor current (18) can be regulated by changing a motor voltage (M) in such a way that the operating speed (23) corresponds to the calibration speed (26) right

Description

The invention relates to a mechanically commutated brush motor for a compressor device with a compressor for generating compressed air, with a rotor and a preferably permanently excited stator, having a current sensor for measuring a motor current, in particular a rotor current, and an electronic control and regulating device that includes a speed control device for the rotor and has a signal input from the current sensor for the measured motor current.

A mechanically commutated brush motor with speed control is an alternative to a speed-controlled brushless direct current motor (BLDC motor). A BLDC motor is relatively expensive compared to a brushed motor. The use of a brush motor for speed control can reduce costs.

Brush motors with speed determination or regulation are already known.

The DE 10 2015 214 019 A1 describes a method for determining the pressure of a small compressor without an additional pressure sensor. For this purpose, the output pressure is determined either from the measured speed with speed sensors or from the current curve.

The EP 0 676 858 B1 describes control electronics that switch between control via electromotive force (EMF) and IxR compensation circuit.

However, speed control via EMF measurement has the disadvantage that the motor to determine the speed --d. H. to measure an induced voltage on the motor - must be operated with periodically briefly interrupted power supply, which is accompanied by noticeable noise. The IxR compensation circuit uses the proportionality between the measured motor current and the associated speed drop. The motor voltage increases proportionally to the motor current. With the IxR compensation circuit, the speed control constancy is subject to the influence of temperature and aging or wear of the brush system. The speed control constancy of the method is therefore limited.

It is desirable to determine the speed, in particular with little noise, over the service life of the brush motor in a largely constant framework.

This is where the invention comes in, the object of which is to provide a device and a method by means of which a mechanically commutated brush motor for a compressor device with a compressor for compressed air generation with a rotor and a preferably permanently excited stator can be operated in an improved manner. In particular, the acoustics and speed constancy of the brush motor should be improved by the method and the device.

With regard to the device, this object is achieved by an improved mechanically commutated brush motor with speed control according to claim 1.

The invention is based on a mechanically commutated brush motor for a compressor device with a compressor for generating compressed air, with a rotor and a preferably permanently excited stator.

The brush motor has a current sensor for measuring a motor current, in particular a rotor current, and an electronic control and regulating device with a speed control device for the rotor and a signal input for the motor current measured by the current sensor.

• - einen Speicher in dem eine Kalibrierkennlinie hinterlegt ist, die eine über einen Verdichtungshub des Verdichters, insbesondere unter kontrollierten Prüfbedingungen, vorzugsweise in einem Neuzustand, des Bürstenmotors, ermittelte Drehzahl angibt,
• - ein Kalibiermodul zum Ermitteln einer Kalibrierdrehzahl aus dem gemessenen Motorstrom, derart, dass insbesondere unter den kontrollierten Prüfbedingungen die aus dem gemessenen Motorstrom ermittelte Drehzahl über die Kalibrierkennlinie auf den Verdichtungshub als die Kalibrierdrehzahl kalibrierbar ist, und
• - ein Bestimmungsmodul zur Ermittlung einer Betriebsdrehzahl, mittels dem im Betrieb aus dem gemessene Motorstrom ein mittlerer Motorstrom bestimmbar ist, wobei aus dem mittleren Motorstrom die Betriebsdrehzahl ermittelbar ist, und
• - ein Vergleichsmodul, mittels dem ein Abgleich zwischen der Betriebsdrehzahl und der Kalibierdrehzahl durchführbar ist, und
• - ein Regelmodul mittels dem der Motorstrom unter Änderung einer Motorspannung derart regelbar ist, dass die Betriebsdrehzahl der Kalibierdrehzahl entspricht, insbesondere weitestgehend konstant bleibt, vorzugsweise die Betriebsdrehzahl innerhalb eines vorbestimmten Varianzbereichs um einen mittels der Kalibrierdrehzahl vorbestimmten Konstantwert liegt.

According to the invention it is provided that the speed control device has:

• a memory in which a calibration characteristic is stored, which indicates a speed determined over a compression stroke of the compressor, in particular under controlled test conditions, preferably when the brush motor is new,
• - A calibration module for determining a calibration speed from the measured motor current, such that, in particular under the controlled test conditions, the speed determined from the measured motor current can be calibrated via the calibration characteristic to the compression stroke as the calibration speed, and
• a determination module for determining an operating speed, by means of which an average motor current can be determined from the measured motor current during operation, the operating speed being able to be determined from the average motor current, and
• - A comparison module by means of which a comparison between the operating speed and the calibration speed can be carried out, and
• - A control module by means of which the motor current can be regulated by changing a motor voltage in such a way that the operating speed corresponds to the calibration speed, in particular remains largely constant, preferably the operating speed is within a predetermined range of variance around a constant value predetermined by means of the calibration speed.

The invention also leads to a compressor device, a compressed air supply system and a vehicle.

As explained above, previous speed controls lead to increased acoustics and / or to a low speed constancy. The invention is based on the idea that, for reasons of acoustics, it is advantageous to operate the brush motor at a constant speed and that this should therefore be regulated using a low-noise method.

The invention is based on the knowledge that the presence of an increase in current due to the compression stroke, in contrast to known approaches, is independent of the state of the brush motor.

By means of the invention, a largely constant speed over the operating time of the motor is now made possible by the comparison between the operating speed and the calibration speed. The invention advantageously enables a largely constant speed over the operating period.

According to the invention, the largely constant speed is achieved in that a calibration characteristic is stored in the memory of the electronic control and regulation device and the measured motor current can be calibrated as a calibration speed by means of the calibration module, in particular under controlled test conditions.

In principle, a calibration characteristic can be determined for many operating states of the brush motor; However, largely defined test conditions that do not have too many imponderables are preferred; in particular, a brushed motor should not have aged too much. In this sense, defined test conditions are to be understood as those that are controlled or controllable. Controlled test conditions are particularly preferably understood to mean a known state of the engine with a defined compression stroke. This is largely the case when the engine is new, for example.

In operation, the speed is kept largely constant over the service life or operating time by determining an operating speed in the determination module, a comparison between the operating speed and the calibration speed in the comparison module and a regulation of the motor current in such a way that the operating speed corresponds to the calibration speed, preferably the operating speed within a predetermined one Variance range is around a constant value predetermined by means of the calibration speed.

According to the concept of the invention, the operating speed can be determined by the determination module from the measured mean motor current, or also via the alternating current component of the brush motor. This alternating current is also known as a current ripple. It is caused by charging and discharging processes in the brush motor.

It is advantageous that the control module can regulate the operating speed by comparing the operating speed and the calibration speed in the comparison module, regardless of tolerances, aging processes of the brush motor and changes in the clamping resistance. This is particularly advantageous since the adaptation of the operating speed cannot be over- or under-compensated in this way.

For the adaptation of the operating speed it is further advantageous that the comparison between the operating speed and the calibration speed in the comparison module can be carried out at predetermined or in any case defined calibration time intervals. The aging process of the brush motor can be compensated for over the service life or operating time of the motor by means of an adjustment at predetermined or at any rate calibration time intervals. A comparison between the operating speed and the calibration speed is provided at a suitable point in time with sufficiently constant conditions, for example at constant voltage and / or constant temperature and / or constant engine power.

In a further development of the brush motor with speed control, the motor current can be measured in the current sensor during a switch-on phase of the motor voltage, the determination module approximating a motor current that contributes to torque generation from the measured motor current.
In this development, it is advantageous to carry out the current measurement on the ground line, also called the low-side. With the low-side current measurement, a measuring resistor is connected as a current sensor between the brush motor and ground. With such a circuit, the motor current can advantageously be measured during a switch-on phase of the motor voltage. A low-side current measurement is simple and inexpensive.

In another development of the brush motor with speed control, the motor current can be measured continuously in the current sensor. In particular, the motor current can be measured during the switch-on phase and a switch-off phase of the motor voltage, the determination module calculating a motor current that contributes to the generation of torque from the measured motor current. In this development, it is advantageous to measure the current on the supply voltage line, including high-side called to perform. With such a high-side current measurement, the measuring resistor is connected between the voltage source and the brush motor. Short-circuit currents can advantageously be detected with a high-side current measurement. The high-side current measurement is still not susceptible to interference on the ground path, which means that the motor current can be measured continuously here.

The electronic control and regulating device can have an analog-digital converter input and a pulse width modulation output. The operating speed of the brush motor can advantageously be adapted by means of an adjustable pulse duty factor with the pulse width modulation output of the electronic control and regulation device. For example, the pulse duty factor can be reduced if the operating speed is too high and increased if the operating speed is too low. The analog-digital converter is designed to convert a pulse-width-modulated signal, in particular a pulse-width-modulated voltage signal, into a digital signal.

In a further development, the brush motor with speed control has a pulse width modulation unit with an adjustable pulse duty factor. The memory of the electronic control and regulating device then also has a lookup table stored with which the pulse duty factor can be determined as a function of the input variables of the engine load and on-board electrical system voltage.

A determination of the pulse duty factor is advantageous in order to avoid complex calculations. This enables the motor voltage to be changed quickly to regulate the motor current.

The current sensor can have a measuring resistor and an amplifier unit. With the measuring resistor, the motor current can be measured indirectly via a drop in the motor voltage. Small changes in the motor voltage signal can be measured with the amplifier unit.

According to a further aspect of the invention, the above-mentioned object is achieved by a compressor device comprising a drive with the brush motor according to the invention and a compressor, in particular a compressor, preferably for a compressed air consumer of a vehicle, such as an air suspension system or a brake system.

The operating speed of the compressor is advantageously regulated by adapting the motor current to the calibration speed. As a result, the operating speed of the compressor is kept as constant as possible by regulating the operating speed to the calibration speed. In particular, this should remain largely constant over the service life or operating time. The operating speed should preferably lie within a predetermined range of variance around a constant value predetermined by means of the calibration speed.

According to a further aspect of the invention, the above-mentioned object is achieved by a compressed air supply system, preferably for a compressed air consumer of a vehicle, in particular an air suspension system and / or a brake system, having a compressor device according to the invention.

According to a further aspect of the invention, the above-mentioned object is achieved by a vehicle having a compressed air supply system according to the invention.

According to a further aspect of the invention, the above-mentioned object is achieved by a method for speed control for operating a compressor device.

• - Messen eines Motorstroms und eines Verdichtungshubs;
• - Ermitteln der zugehörigen Drehzahlen aus der Messung des Motorstroms und der Messung des Verdichtungshubs;
• - Kalibrieren der Drehzahl aus der Messung des Motorstroms über die Drehzahlen aus der Messung des Verdichtungshubs als Kalibrierdrehzahl;
• - Messen des Motorstroms im Betrieb und Ermittlung einer Betriebsdrehzahl;
• - Abgleichen zwischen der Betriebsdrehzahl und der Kalibierdrehzahl und
• - Regeln des Motorstroms derart, dass die Betriebsdrehzahl auf die Kalibrierdrehzahl geregelt wird, insbesondere weitestgehend konstant bleibt, vorzugsweise die Betriebsdrehzahl innerhalb eines vorbestimmten Varianzbereichs um einen mittels der Kalibrierdrehzahl vorbestimmten Konstantwert liegt.

The method according to the invention has the following steps:

• - measuring a motor current and a compression stroke;
• - Determining the associated speeds from the measurement of the motor current and the measurement of the compression stroke;
• - Calibrating the speed from the measurement of the motor current via the speeds from the measurement of the compression stroke as the calibration speed;
• - Measuring the motor current during operation and determining an operating speed;
• - Adjustment between the operating speed and the calibration speed and
• Regulation of the motor current in such a way that the operating speed is regulated to the calibration speed, in particular remains largely constant, preferably the operating speed is within a predetermined range of variance around a constant value predetermined by means of the calibration speed.

The method according to the invention advantageously enables speed regulation independently of the state of the brush motor. The measurement of the motor current, the comparison between the operating speed and the calibration speed and the regulation of the motor current can be carried out automatically, without individual process steps requiring manual operation by the user.

Furthermore, the method includes an approximation of a motor current that contributes to the generation of torque from the measured motor current.

In a further development of the method, the comparison of the operating speed and the calibration speed takes place at defined calibration time intervals, in particular when a suitable point in time with sufficiently constant conditions is proven via the motor current measurement.

In a possible development of the method, a pulse duty factor of a pulse width modulation is determined. The pulse duty factor is determined in a lookup table as a function of input variables, in particular as a function of input variables such as load and vehicle electrical system voltage. By defining the duty cycle in the lookup table, memory space can be saved and / or faster control of the operating speed can be achieved.

The concept of the invention is not limited to a compressed air supply system or a compressed air consumer of a vehicle, such as, for example, an air suspension system or a brake system, having a compressor for generating compressed air using a brush motor. Rather, the method on which the invention is based serves as a general method for operating brush motors at constant speeds.

Embodiments of the invention will now be described below with reference to the drawing. This is not necessarily intended to represent the embodiments true to scale; rather, the drawing, where useful for explanation, is in a schematic and / or slightly distorted form. With regard to additions to the teachings that can be seen directly from the drawing, reference is made to the relevant prior art. It must be taken into account here that various modifications and changes relating to the shape and detail of an embodiment can be made without deviating from the general idea of the invention. The features of the invention disclosed in the description, in the drawing and in the claims can be essential for the development of the invention both individually and in any combination. In addition, all combinations of at least two of the features disclosed in the description, the drawing and / or the claims fall within the scope of the invention. The general idea of the invention is not restricted to the exact form or the detail of the preferred embodiment shown and described below or restricted to an object that would be restricted in comparison to the object claimed in the claims. In the case of the specified measurement ranges, values lying within the stated limits should also be disclosed as limit values and be able to be used and claimed as required. Further advantages, features and details of the invention emerge from the following description of the preferred embodiments and with reference to the drawing.

• 1 eine Verdichtereinrichtung mit Bürstenmotor, Stromsensor und elektronische Steuer- und Regeleinrichtung gemäß einer bevorzugten Ausführungsform;
• 2A und 2B eine Verdichtereinrichtung mit Bürstenmotor nach einer ersten Ausführungsform und einer zweiten Ausführungsform;
• 3 einen Stromverlauf eines Kompressors und die daraus durch Filterung zu gewinnenden Signale;
• 4A, 4B, 4C 4D simulierte Stromverläufe bei unterschiedlichen Bürstenmotoreinstellungen ;
• 5 Verfahren zur Drehzahlregelung gemäß einer bevorzugten Ausführungsform; und
• 6 ein Fahrzeug mit Druckluftversorgungsanlage gemäß einer bevorzugten Ausführungsform.

The drawing shows in detail:

• 1 a compressor device with brush motor, current sensor and electronic control and regulating device according to a preferred embodiment;
• 2A and 2 B a brush motor compressor device according to a first embodiment and a second embodiment;
• 3 a current curve of a compressor and the signals to be obtained therefrom by filtering;
• 4A , 4B , 4C 4D simulated current curves with different brush motor settings;
• 5 Method for speed control according to a preferred embodiment; and
• 6th a vehicle with a compressed air supply system according to a preferred embodiment.

1 shows a compressor device 100 with brush motor 10 , Current sensor 14th and electronic control and regulation equipment 12th . The brush motor 10 also has a rotor 9 and a stator 11 on.

The current sensor 14th is designed a motor current, in particular a rotor current, as a function of time, also as a measured motor current 18th designated to measure. The measured motor current 18th is from the current sensor 14th via a signal input 16 to the electronic control and regulation device 12th passed on.

The electronic control and regulation device 12th has a speed control device 13 with a memory 20th , a calibration module 24 , a determination module 28 , a comparison module 28 and a control module 34 .

In the storage room 20th is a calibration curve 22nd stored, the one via a compression stroke 15th of the compressor 8th determined speed 17th indicates. The one about the compression stroke 15th determined speed 17th is under controlled test conditions, preferably when new, of the brush motor 10 easily measurable. Also is in the memory 20th a lookup table 29 deposited with the lookup table 29 can control the operating speed 23 done faster because a mathematical calculation is used in the Using the lookup table 29 is not needed. In the lookup table 29 is a duty cycle TV a pulse width modulation unit depending on the input variables 31 load L. and electrical system voltage BNS deposited.

In the calibration module 24 becomes a calibration speed 26th from the measured motor current 18th , the under controlled test conditions, preferably when new, the brush motor 10 is measured, determined. To determine the calibration speed 26th is derived from the measured motor current 18th determined speed 17th via the calibration curve 22nd on the compression stroke 15th calibrated. The determination module 28 received during operation of the brush motor 10 via the signal input 16 the measured motor current 18th . From the motor current measured during operation 18th is an average motor current 21st determinable, from the mean motor current 21st the operating speed 23 can be determined.

The comparison module 30th receives the operating speed 23 and the calibration speed 26th and is designed an adjustment 32 between the operating speed 23 and the calibration speed 26th perform. With the comparison module 30th it can thus be determined whether the operating speed 23 and the calibration speed 26th differ from each other.

The control module 34 is designed for this by the comparison module 30th a result of the match 32 to receive and then the motor current 18th while changing a motor voltage M. to regulate so that the operating speed 23 the calibration speed 26th corresponds. The operating speed remains 23 within a predetermined range of variance V , which by one means of the calibration speed 26th predetermined constant value K lies.

2A shows a compressor device 100 ' with brush motor 10 ' according to a first embodiment. In this first embodiment has a compressor device 100 ' an electronic control and regulation device 12 ' , a current sensor 14 ' with measuring resistor R _SEN ' and amplifier unit 38 ' that between crowd 39 ' and engine load 40 ' is built in, and a switch 36 ' that between the engine load 40 ' and the current sensor 14 ' is built in. The brush motor 10 ' is in this embodiment a DC voltage motor, which is from a voltage source 41 ' is supplied.

In this embodiment, the electronic control and regulation device 12 ' a microcontroller. The electronic control and regulation device 12 ' has an analog-digital converter input ADC Input and a pulse width modulation output PWM Output. The analog-digital converter ADC is designed to convert a pulse-width modulated signal into a digital signal. The pulse width modulation output PWM Output of the electronic control and regulation device 12 ' is designed to control the operating speed 23 of the brush motor 10 ' adapt by an adjustable duty cycle TV. The duty cycle TV is present by the duration of the switch-on phase t _ON the motor voltage for the duration of the pulse period, i.e. the switch-on and switch-off phase t _{ON + OFF} , certainly.

The desk 36 ' is an N-channel MOSFET switch. An N-channel MOSFET has a gate, drain and source. With the switch open 36 ' the gate of the MOSFET is via a gate resistor R _G ' at the same potential as the supply voltage from the voltage source 41 ' , the MOSFET is not activated and the brush motor 10 ' is not supplied with voltage. The gate resistor R _G ' is between the pulse width modulation output PWM Output and switch 36 'switched to the gate when the switch is open 36 ' to regulate to zero voltage. If the switch closes, the gate voltage of the N-channel MOSFET drops, the MOSFET controls through and the brush motor 10 ' is supplied with voltage. Such a course of the voltage is shown in 4A , 4B , 4C and 4D to see.

It becomes a diode 42 ' about the engine load 40 ' switched to that from the engine 10 ' when turning off the switch 36 ' to reduce the generated tension.

In this embodiment the current sensor has 14 ' a measuring resistor R _SEN ' , via which the falling motor voltage signal is measured and converted into a motor current signal. With the help of the amplifier unit 38 ' small changes in the motor voltage signal can also be measured. In this exemplary embodiment, the amplifier unit has a differential amplifier 43 ' and a boost resistor R _LP ' on. With the gain resistor R _LP ' the gain can be adjusted. The arrangement also has a capacitor C _LP ' on. The condenser C _LP ' serves to filter the output voltage. With such an arrangement, the motor current is only available during a switch-on phase t _ON the motor voltage measurable; this according to a first measurement method, which has a switch-on phase t _ON of the brush motor 10 ' is working. Such a current measurement is simple and inexpensive.

2 B shows a compressor device 100 " with brush motor 10 " according to a second embodiment. This second embodiment of the compressor device 100 " has the same components as the compressor device 100 " of the first embodiment 2A . The functionality components such as the control and regulation device 12 '' , the switch 36 '' and the brush motor 10 '' with engine load 40 '' and diode 42 '' has not changed in this structure.

The embodiment of the compression device 100 '' out 2 B differs from the embodiment of the compression device 100 ' out 2A in that the one electronic control and regulating device 12 " with measuring resistor R _SEN " and amplifier 28 "between the voltage source 41 '' and the engine load 40 '' is arranged. With such an arrangement, short-circuit currents can be detected. This current measurement is also not susceptible to interference on the ground path, which means that the motor current can be measured continuously here; this according to a second measurement method, which has an on and off phase t _{ON + OFF} of the brush motor 10 '' works and measures the motor current continuously over an entire period.

3 shows a motor current curve 18 ' of a compressor, in particular a compressor, and the signals to be obtained therefrom by filtering. The in 1 measured motor current shown symbolically 18th is in 3 specifically as a motor current curve measured by way of example 18 ' and shows an idealized course of a motor current of a two-stage compressor. One revolution of the rotor is displayed with T. The motor current curve 18 ' shows an approximately sinusoidal curve with current ripples 49 . A motor current signal results from a superposition of the current curve of the brush motor resulting from the compression stroke 48 and the current curve of the brush motor resulting from the commutation 50 . Both the compression stroke 48 as well as commutation 50 are as a filtered signal 47 , 49 shown. From the course of the current 46 the mean motor current 21st in the in 1 determination module shown 28 determine. The operating speed can be obtained from the mean motor current 23 be determined.

Since with a two-stage compressor the current is reduced during compression 46 of the flow of expansion 44 differs, the maxima of the motor current are different. The current ripple 49 arise through mechanical commutation 50 of the brush motor. The filtered signals of the compression stroke 48 and commutation 50 are shown separately.

To avoid a dependency on the in 1 measured motor current shown symbolically 18th certain settings on the engine are to be clarified in 4A , 4B , 4C and 4D Motor current curves 18 " as simulated motor current curves 54 , 54 ' , 54 '' , 54 ''' depending on the course of the gate voltage of the MOSFET switch 52 , 52 ' , 52 '' , 52 ''' , and variables such as the frequency of the pulse width modulation mode ( PWM Operation), the duty cycle of the PWM and the load.

4A , 4B , 4C and 4D are described jointly in the following in order to also include the motor current that contributes to torque generation I _t1 , I _t2 from the measured motor current 18th to explain. Depending on the measurement method, the contributing motor current I _t1 , I _t2 either according to the first measurement method mentioned above ( 2A) the switch-on motor current I _t1 = M _ON during a switch-on phase t _ON or according to the above-mentioned second measurement method ( 2 B) the switch-on and switch-off motor current I _t2 = M _{ON + OFF} during a switch-on and switch-off phase t _{ON + OFF} be. In 4A , 4B , 4C and 4D are inrush motor current M _ON as the contributing motor current I _t1 according to the above first measurement method and switch-on and switch-off motor current M _{ON + OFF} as the contributing motor current I _t2 according to the above-mentioned second measurement method for the switch-on phase t _ON and switch-on and switch-off phases t _{ON + OFF} each shown.

4A shows a simulated motor current curve 54 a brush motor at 9V gate voltage, 4kHz PWM Operating frequency, 75% duty cycle and low load.

4B shows a simulated motor current curve 54 ' a brush motor at 12V gate voltage, 4kHz PWM Operating frequency, 60% duty cycle and low load.

4C shows a simulated motor current curve 54 '' a brush motor at 12V gate voltage, 4kHz PWM Operating frequency, 75% duty cycle and high load.

4D shows a simulated motor current curve 54 ''' a brush motor at 16V gate voltage, 4kHz PWM Operating frequency, 45% duty cycle and low load.

When switching on the gate voltage 52 , 52 ' , 52 '' , 52 ''' the motor current increases 54 , 54 ' , 54 '' , 54 ''' at. This corresponds to the course of the motor current 54 , 54 ' , 54 '' , 54 ''' during the switch-on phase t _ON the gate voltage 52 , 52 ' , 52 '' , 52 ''' . The increase depends on the operating conditions.

During the switch-off phase t _OFF , i.e. with the gate voltage switched off 52 , 52 ' , 52 '' , 52 ''' the motor current falls 54 , 54 ' , 54 '' , 54 ''' from. This drop also depends on the operating conditions. From the mean motor current, which as in 3 can be determined, the operating speed 23 to calculate.

5 shows a method for speed control 200 according to a preferred embodiment. The first step in the speed control method S1 the motor current 18th and the Compression stroke 15th measured under controlled test conditions. In a second step S2 is based on the measurement of the motor current 18th and the measurement of the compression stroke 15th an associated speed 17th determined. The speed from the measurement of the motor current is calculated in a third step S3 on the speed 17th from the measurement of the compression stroke 15th calibrated. The speed determined in this way is used as the calibration speed 26th used. When the compressor is running 8th becomes the motor current 18th measured and from this an operating speed 23 determines S4. The operating speed 23 is derived from an averaged motor current 21st calculated. In a next step S5 becomes the calibration speed 26th , which has been determined under controlled test conditions, and the operating speed 23 matched with each other. Give way to the calibration speed 26th and the operating speed 23 from each other, so is a final step S6 the motor current 18th regulated so that the operating speed 23 on the calibration speed 26th is regulated and thus remains largely constant. The operating speed is preferably 23 within a predetermined range of variance V by one by means of the calibration speed 26th predetermined constant value K .

6th shows a vehicle 600 with compressed air supply system 500 according to a preferred embodiment. The compressed air supply system 500 can compressed air consumer 505 like an air suspension system 510 or a braking system 520 , of the vehicle 600 drive.

List of reference symbols

8th

compressor

9

rotor

10, 10 ', 10 "

Brush motor

11

stator

12, 12 ', 12 "

electronic control device

13

Speed control device

14, 14 ', 14 "

Current sensor

15th

Compression stroke

16

Signal input

17th

rotational speed

18th

measured motor current

18 '

motor current curve measured as an example

18 "

Motor current curve simulated depending on certain motor settings

20th

Storage

21st

mean motor current

22nd

Calibration curve

23

Operating speed

24

Calibration module

26th

Calibration speed

28

Determination module

29

Lookup table

30th

Comparison module

31

Input variables

32

adjustment

34

Control module

36 ', 36 "

counter

37 ', 37 "

Pulse width modulation unit

38 ', 38 "

Amplifier unit

39 '

Dimensions

40 ', 40 "

Engine load

41 ', 41 "

Voltage source

42 ', 42' '

diode

43 ', 43' '

Differential amplifier

44

Electricity in expansion

46

Electricity in compression

47

filtered signal compression stroke

48

Compression stroke

49

filtered signal commutation, alternating current component

50

Commutation

52, 52 ', 52' ', 52' ''

Gate voltage 54, 54 ', 54 ", 54"' motor current

100, 100 ', 100' '

Compressor device

200

Speed control method

500

Compressed air supply system

505

Compressed air consumer

510

Air suspension system

520

Braking system

600

vehicle

ADC

Analog-to-digital converter

ADC input

Analog-digital converter input

BNS

Electrical system voltage

C _LP ', C _LP ''

capacitor

I _t1 , I _t2

Contributing motor current according to the first and second measurement method

K

predetermined constant value

L.

load

M.

Motor voltage

M _ON

Inrush motor current

M _{ON + OFF}

On and off motor current

PWM

Pulse width modulation

PWM

Output pulse width modulation output

R _G ', R _G ''

Gate resistance

R _LP ', R _LP ''

Reinforcement Resistance

R _SEN ', R _SEN ''

Measuring resistor

S1

Measure a motor current and a compression stroke

S2

Determining the speeds

S3

Calibrate

S4

Measuring the motor current during operation

S5

Compare

S6

Regulation of the motor current

T

Rotation of the rotor

TV

Duty cycle

t _ON

Switch-on phase

t _OFF

Switch-off phase

t _{ON + OFF}

Switch-on and switch-off phase

Δt

Calibration time intervals

V

predetermined range of variance

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

• DE 102015214019 A1 [0004]
• EP 0676858 B1 [0005]

Claims (17)

Mechanically commutated brush motor (10) for a compressor device (100) with a compressor (8) for generating compressed air, with a rotor (9) and a preferably permanently excited stator (11), having a current sensor (14) for measuring a motor current (18), in particular a rotor current, and an electronic control and regulating device (12) which has a speed control device (13) for the rotor and a signal input (16) for the motor current (18) measured by the current sensor (14), characterized in that the speed control device (13) has: a memory (20) in which a calibration characteristic (22) is stored which indicates a speed (17) determined via a compression stroke (15) of the compressor (8), a calibration module (24) for determining a calibration speed ( 26) from the measured motor current (18), in such a way that the speed (17) determined from the measured motor current (18) is transferred to the compression stroke (15) as di via the calibration characteristic (22) e calibration speed (26) can be calibrated, and a determination module (28) for determining an operating speed (23), by means of which an average motor current (21) can be determined from the measured motor current (18) during operation, the average motor current (21) being the operating speed (23) can be determined, and a comparison module (30), by means of which a comparison (32) between the operating speed (23) and the calibration speed (26) can be carried out, and a control module (34) by means of which the motor current (18) can be regulated by changing a motor voltage (M) in such a way that the operating speed (23) corresponds to the calibration speed (26), in particular remains largely constant, preferably the operating speed (23) within a predetermined range of variance (V) by a means of the calibration speed (26) predetermined constant value (K). Brush motor (10) with speed control according to Claim 1 , characterized in that the operating speed (23) determined from the measured motor current (18) can be determined by the determination module (28) via an alternating current component (49) of the brush motor (10). Brush motor (10) with speed control according to the Claim 1 or 2 , characterized in that the operating speed (23) with the control module (34), by the comparison (32) between the operating speed (23) and the calibration speed (26) in the comparison module (30), regardless of tolerances, aging processes of the brush motor (10 ) and changes in the clamping resistance can be regulated. Brush motor (10) with speed control according to one of the Claims 1 to 3 , characterized in that the comparison (32) between the operating speed (23) and the calibration speed (26) can be carried out in the comparison module (30) at regular intervals. Brush motor (10) with speed control according to one of the Claims 1 to 4th , characterized in that the motor current (18) can be measured in the current sensor (14) during a switch-on phase (t _ON ) of the motor voltage (M), the determination module (28) generating a motor current (I _t1 , I _t2 ) that contributes to torque _generation from the measured motor current (18) approximated. Brush motor (10) with speed control according to one of the Claims 1 to 4th , characterized in that the motor current (18) can be measured continuously in the current sensor (14), in particular during the switch-on phase (t _ON ) and a switch-off phase (t _OFF ) of the motor voltage (M), the determination module (28) contributing to the generation of torque Motor current (I _t1 , I _t2 ) calculated from the measured motor current (18). Brush motor (10) with speed control according to one of the Claims 1 to 6th , characterized in that the electronic control and regulation device (12) has an analog-to-digital converter (ADC) input and a pulse width modulation (PWM) output. Brush motor (10) with speed control according to Claim 7 , characterized in that a pulse width modulation unit (37) with an adjustable pulse duty factor (TV), wherein a lookup table (29) is additionally stored in the memory (20) of the electronic control and regulation device (12) with which the pulse duty factor ( TV) can be determined as a function of input variables (31) load (L) and vehicle electrical system voltage (BNS). Brush motor (10) with speed control according to one of the Claims 1 to 8th , characterized in that the current sensor (14) has a measuring resistor (R _SEN ) and an amplifier unit (38). Compressor device (100) comprising a drive with a brush motor (10) according to one of the Claims 1 to 9 and a compressor (8), in particular a compressor, preferably for a compressed air consumer (505) of a vehicle (600), such as an air suspension system (510) or a brake system (520). Compressor device (100) after Claim 10 , characterized in that the operating speed (23) of the compressor (8) is kept constant by adjusting the motor current (18). Compressed air supply system (500), preferably for a compressed air consumer (505) of a vehicle (600), in particular an air suspension system (510) and / or a brake system (520), having a compressor device (100) according to one of the Claims 10 to 11 . Vehicle (600) having a compressed air supply system (500) according to Claim 12 . Method for speed control (200) for operating a compressor device (100) according to one of the Claims 10 to 11 with a brush motor (10) according to one of the Claims 1 to 9 comprising the steps of: - measuring (S1) a motor current (18) and a compression stroke (15); - Determination (S2) of the associated speeds (17) from the measurement of the motor current (18) and the measurement of the compression stroke (15); - Calibrating (S3) the speed from the measurement of the motor current (18) via the speeds (17) from the measurement of the compression stroke (15) as the calibration speed (26), - measuring (S4) the motor current (18) during operation and determining a Operating speed (23); - matching (S5) between the operating speed (23) and the calibration speed (26) and - regulating (S6) the motor current (18) in such a way that the operating speed (23) is regulated to the calibration speed (26), in particular remains largely constant, the operating speed (23) is preferably within a predetermined variance range (V) around a constant value (K) predetermined by means of the calibration speed (26). Method (200) according to Claim 14 , characterized in that the method further comprises an approximation of a motor current (I _t1 , I _t2 ) contributing to the generation of torque from the measured motor current (18). Method (200) according to Claim 14 or 15th , characterized in that the adjustment of the operating speed (23) and the calibration speed (26) takes place at predetermined calibration time intervals (Δt). Method (200) according to one of the Claims 14 to 16 , characterized in that a pulse duty factor (TV) of a pulse width modulation (PWM) is determined, in particular that the pulse duty factor (TV) is determined in a lookup table (29) as a function of input variables (31), in particular load (L) and on-board voltage ( BNS) is determined.

Images