Control device for operating an electric machine, electric machine, method

Abstract

The present invention relates to a control device (8) for operating a motor (1), wherein the motor (1) has a rotor (2), a stator (4) and a power electronics device (7), wherein the rotor (2) is arranged in an anti-rotation manner on a shaft (3) rotatably mounted in a housing, wherein the stator (4) is arranged in a fixed manner relative to the housing and has a stator winding (5) having at least three phases (U, V, W), wherein the power electronics device (7) has a plurality of switching elements, through which the phases (U, V, W) are electrically connected / electrically connectable to an energy storage device (6), and wherein the control device (8) has a first computing unit (10) and a second computing unit (11), and the control device (8) is configured to determine, by means of the computing units (10, 11), a control signal for controlling the switching elements. The first computing unit (10) is configured to determine the control signal for controlling the switching elements based on the rated speed (RPM) of the rotor (2). Soll The second calculation unit (11) is connected to the first calculation unit (10) via communication technology, and the second calculation unit (11) is configured to determine the control signal based on the value of the rated voltage vector (|U|) and the actual rotational speed of the rotor (2), wherein the second calculation unit (11) is connected to the first calculation unit (10) via communication technology, and the second calculation unit (11) is configured to determine the control signal based on the value of the rated voltage vector (|U|) and the actual rotational angle of the rotor (2).

Description

Technical Field

[0001] This invention relates to a control device for operating an electric motor, wherein the motor has a rotor, a stator, and power electronics, wherein the rotor is arranged in an anti-rotational manner on a shaft rotatably mounted in a housing, wherein the stator is arranged in a fixed manner relative to the housing and has stator windings having at least three phases, wherein the power electronics have a plurality of switching elements through which the phases are electrically connected / possibly connected to an energy storage device, and wherein the control device has a first computing unit and a second computing unit, and the control device is configured to determine, by means of the computing units at the control device, to operate the switching elements.

[0002] Furthermore, the present invention relates to a motor having such a control device.

[0003] Furthermore, the present invention relates to a method for operating an electric motor by means of such a control device. Background Technology

[0004] An electric motor typically has a rotor and a stator. The rotor is arranged anti-rotationally on a shaft, which is rotatably housed within a housing. The stator is fixed relative to the housing, allowing the rotor and stator to twist relative to each other. The stator usually has stator windings with at least three phases. These phases are arranged around the rotor so that the rotor can be driven or rotated by properly energizing these phases. To ensure proper energization of the phases, power electronics with multiple switching elements are provided. These phases are electrically connected to or disconnected from an energy storage device via the power electronics or switching elements.

[0005] To operate a motor, a control device is known from the prior art, comprising a first computing unit and a second computing unit, wherein the control device is configured to determine, by means of the computing units, a control signal for operating the switching elements. According to the known control device, the first computing unit is typically configured to determine the rated phase voltage for each phase based on the rated speed of the rotor, the actual speed of the rotor, and the actual rotation angle of the rotor. The second computing unit is then configured to determine the control signal for operating the switching elements based on the determined rated phase voltage. The desired rated phase voltage is then applied to these phases by operating the switching elements according to the control signal. For example, this is done by switching the switching elements of the power electronics in a pulse-width modulated manner. Summary of the Invention

[0006] The control device according to the invention has the advantage of reducing the computational power required in the first calculation unit to determine the control signal compared to prior known control devices. According to the invention, for this purpose, the first calculation unit is configured to determine the value of the rated voltage vector for a phase based on the rated speed of the rotor and the actual speed of the rotor; wherein the second calculation unit is configured to determine the control signal based on the value of the rated voltage vector and the actual rotation angle of the rotor. For this purpose, according to the invention, the second calculation unit is connected to the first calculation unit via communication technology, such that the first calculation unit can provide the value of the rated voltage vector to the second calculation unit. The rated speed is to be understood here as a predetermined speed that should be achieved by controlling the switching elements according to the control signal. The rated voltage vector is the voltage vector corresponding to the rated phase voltage. For example, the rated phase voltage is described by the rated voltage vector in a coordinate system rotating with the rotor or in a coordinate system fixed relative to the stator. Here, the first calculation unit only determines the value of the rated voltage vector. Preferably, the second calculation unit is configured to determine the orientation of the rated voltage vector and / or the individual rated phase voltages. The control signal is preferably determined such that, when controlling the power electronic device, an actual phase voltage with a sinusoidal variation process is applied to each of these phases according to the control signal.

[0007] According to a preferred embodiment, the control device is configured as a microcontroller. Therefore, the control device is an electrical component, i.e., a microcontroller, which has both a first computing unit and a second computing unit. The computing units are specifically arranged on the same printed circuit board as the microcontroller. By configuring the control device as a microcontroller, a space-saving approach is achieved.

[0008] Preferably, the first computing unit is the main computing unit of the microcontroller. Since the first computing unit is the main computing unit, only a reduced amount of computing power from the main computing unit is needed to determine the control signals. Therefore, the main computing unit still has sufficient computing power for other calculation processes that need to be performed by the main computing unit.

[0009] Preferably, the second computing unit is an auxiliary computing unit of the microcontroller. Such an auxiliary computing unit is typically already included in the microcontroller as a peripheral unit. Therefore, there is no need to set up an additional computing unit for determining the control signals, which would otherwise not exist. Preferably, the auxiliary computing unit is a timer of the microcontroller. The timer has a particularly short period, making it possible to determine temporally successive control signals with a small time interval between them. This allows for precise adjustment of the motor using a control device.

[0010] According to a preferred embodiment, a first calculation unit has a first cycle time, and a second calculation unit has a second cycle time, wherein the second cycle time is shorter than the first cycle time. A particularly small time interval between control signals is advantageous when determining time-sequential control signals. Such a small time interval is unnecessary when determining time-sequential values ​​of the rated voltage vector. Therefore, it is particularly advantageous to have a second calculation unit with a shorter second cycle time and a first calculation unit with a longer first cycle time. In particular, the first calculation unit forms a slow first regulator or speed regulator, while the second calculation unit forms a faster second regulator compared to the first regulator. For example, the first calculation unit has a cycle time of approximately 1 ms. For example, the second calculation unit has a cycle time of approximately 50 μs.

[0011] According to a preferred embodiment, the control device includes an apparatus in which a second computing unit is configured to determine the actual rotation angle of the rotor based on data received by means of the apparatus. Because the second computing unit requires this actual rotation angle to determine the control signal, the second computing unit is particularly suitable for determining the rotation angle due to its short cycle time. In particular, the apparatus is connected / connectable to the rotation angle sensor of the motor via communication technology, so that data detected by the rotation angle sensor can be provided to the apparatus.

[0012] According to a preferred embodiment, a first calculation unit is configured to determine at least one permissible maximum phase current, and a second calculation unit is pre-programmed with the determined maximum phase current, wherein the second calculation unit is configured to determine a control signal based on the maximum phase current. The maximum phase current is here understood as the maximum permissible value of the current flowing through these phases. By pre-programming the maximum phase current, a particularly smooth change in the actual rotor speed is achieved.

[0013] According to a preferred embodiment, a first calculation unit is configured to determine at least one rated commutation angle and to pre-given the determined rated commutation angle to a second calculation unit, wherein the second calculation unit is configured to determine a control signal based on the rated commutation angle. The rated commutation angle is to be understood herein as an angle pre-given to induce pre-commutation of the phase. The desired pre-commutation or rated commutation angle is generally pre-given in relation to the rotational speed. Because the first calculation unit already knows the rated rotational speed and the actual rotational speed in order to determine the value of the rated voltage vector, the first calculation unit is particularly suitable for determining the rated commutation angle.

[0014] The motor according to the invention comprises a rotor, a stator, and power electronics, wherein the rotor is arranged in an anti-rotational manner on a shaft rotatably mounted in a housing, wherein the stator is arranged fixed relative to the housing and has stator windings having at least three phases, and wherein the power electronics have a plurality of switching elements through which the phases are electrically connected / possibly connected to an energy storage device, and the motor is superior to the control device according to the invention. The aforementioned advantages are also obtained therefrom. Other preferred features and combinations thereof are derived from the foregoing description and from the present invention application.

[0015] According to a preferred embodiment, the machine has an angle sensor for monitoring the actual rotation angle of the rotor. Preferably, the angle sensor has a measuring sensor (Messwertgeber), particularly a magnetic field generator, that rotates with the rotor, and a receiver, particularly a magnetic field sensitive element, that is fixed relative to the housing.

[0016] According to the invention, a method for operating an electric motor includes a rotor, a stator, power electronics, and a control device. The rotor is arranged in an anti-rotational manner on a shaft rotatably mounted in a housing. The stator is arranged relatively fixed to the housing and has stator windings having at least three phases. The power electronics have a plurality of switching elements. The control device determines control signals for manipulating the switching elements, and the switching elements are manipulated according to the control signals such that the phases are selectively electrically connected to or disconnected from an energy storage device via the switching elements. The method is advantageous according to the invention in that: a first calculation unit of the control device determines the values ​​of the rated voltage vectors for these phases based on the rated speed for the rotor and the actual speed of the rotor; and a second calculation unit of the control device, connected to the first calculation unit via communication technology, determines the control signals based on the values ​​of the rated voltage vectors and the actual rotation angle of the rotor. Attached Figure Description

[0017] The invention is described in more detail below with reference to the accompanying drawings.

[0018] Figure 1 A motor with control devices is shown.

[0019] Figure 2 A schematic detailed view of the control device is shown, and

[0020] Figure 3 A method for operating a motor is shown. Detailed Implementation

[0021] Figure 1A schematic diagram of a motor 1 is shown. In this invention, machine 1 is an electrically commutated machine 1. Machine 1 has a rotor 2, which is a permanent magnet in this invention. The rotor 2 is arranged on a rotor shaft 3, which is rotatably mounted in a housing (not shown) of machine 1. Furthermore, machine 1 has a stator 4 with stator windings 5. According to... Figure 1 In the embodiment shown, the stator winding 5 includes three phases U, V, and W. Phases U, V, and W are arranged in a manner distributed around the rotor 2 such that the rotor 2 can be driven or rotated by properly energizing phases U, V, and W.

[0022] An energy storage device 6 is provided to machine 1. The energy storage device 6 is electrically connected / possibly connected to phases U, V, and W via a power electronics device 7 of machine 1. For this purpose, the power electronics device 7 has, for example, a number of half-bridges corresponding to the number of phases U, V, and W, wherein each half-bridge has two semiconductor switches, and each of the phases U, V, and W is connected / possibly connected to the energy storage device 6 via a separate additional half-bridge.

[0023] In addition, machine 1 also has a function for monitoring the actual rotation angle of rotor 2. Angle sensor 9. Angle sensor 9, for example, has a magnetic field generator as a measuring sensor and a magnetic field sensing element as a receiver.

[0024] In addition, the motor 1 also has a current measuring device 17, which is configured to detect the actual phase current I flowing through phases U, V and W. Sum In this invention, the current measuring device 17 is electrically connected to the power electronic device 7 and is configured to detect the actual phase current I in the region of the power electronic device 7. Sum .

[0025] In addition, machine 1 also has a control device 8 configured to determine control signals for operating the switching elements of power electronics 7, and to operate power electronics 7 according to these control signals. Control device 8 is connected to angle sensor 9 via communication technology, allowing data detected by angle sensor 9 to be provided to control device 8 to determine the control signals. Control device 8 is also connected to current measuring device 17 via communication technology, allowing the control device 8 to also receive the detected actual phase current I. Sum .

[0026] Figure 2A schematic detailed view of a control device 8 is shown. The control device 8 is a microcontroller 8. The microcontroller 8 has a first computing unit 10 and a second computing unit 11. The first computing unit 10 is the main computing unit of the microcontroller 8, and the second computing unit 11 is an auxiliary computing unit or timer 11 of the microcontroller 8. Here, the computing units 10 and 11 are distinguished by their cycle times. The first computing unit 10 has a first cycle time that is longer than the second cycle time of the second computing unit 11.

[0027] The first calculation unit 10 is configured here to calculate based on the rated speed RPM of the rotor 2. Soll Based on the actual rotational speed of rotor 2, the value of the rated voltage vector |U| for phases U, V, and W is determined. The second calculation unit 11 is connected to the first calculation unit 10 via communication technology and is configured to calculate the rated voltage vector value |U| and the actual rotational angle of rotor 2. Determine the control signal.

[0028] For this purpose, the first calculation unit 10 has a value determination unit 12, a commutation angle pre-setting unit 13, and a maximum current pre-setting unit 14. The second calculation unit 11 has a control signal determination unit 15 and a device 16, which is a rotor angle determination unit 16.

[0029] The control device 8 is connected to the angle sensor 9 via communication technology using the rotor angle determination unit 16. The rotor angle determination unit 16 is configured to determine the actual rotation angle of the rotor 2 based on data detected by the angle sensor 9. The rotor angle determination unit 16 is also connected to the control signal determination unit 15 and the value determination unit 12 via communication technology, so as to provide these units 15 and 12 with the determined actual rotation angle.

[0030] With the help of the control signal determination unit 15, the control device 8 is connected to the current measuring device 17 via communication technology, so that the actual phase current I detected by the current measuring device 17 is... Sum It can be provided to the control signal determination unit 15.

[0031] The numerical determination unit 12 is constructed based on the actual rotation angle. Or based on the actual turning angle The actual rotational speed of rotor 2 is determined by observing the change process. Furthermore, the numerical determination unit 12 is configured to receive the rated rotational speed (RPM) of rotor 2. Soll For this purpose, the numerical determination unit 12 is connected to other control devices (not shown) via communication technology. The numerical determination unit 12 is configured to determine the value based on the rated speed RPM. SollThe rated voltage vector value |U| is determined based on the actual rotational speed. On the output side, the value determination unit 12 is connected via communication technology to the commutation angle pre-setting unit 13, the maximum current pre-setting unit 14, and the control signal determination unit 15 to provide the determined value |U| to these units 13, 14, and 15.

[0032] The commutation angle pre-setting unit 13 is connected to the control signal determining unit 15 via communication technology, so that the actual phase current I can be provided to the commutation angle pre-setting unit 13 through the control signal determining unit 15. Sum The commutation angle pre-setting unit 13 is configured to, based on the received value |U| and the received actual phase current I... Sum Determine the rated commutation angle and rated commutation angle Provided to the control signal determination unit 15.

[0033] The maximum current pre-setting unit 14 is configured to determine the maximum allowable phase current I based on the received value |U|. Max And will allow the maximum phase current I Max Provided to the control signal determination unit 15.

[0034] Finally, the control signal determination unit 15 is configured to determine the value |U| and the rated commutation angle. Maximum allowable phase current I Max Actual turning angle and actual phase current I Sum The control signals for the switching elements of the power electronic device 7 are determined.

[0035] In the following text, see reference Figure 3 The flowchart describes an advantageous method for operating motor 1 using control device 8.

[0036] In the first step S1, the angle sensor 9 monitors the actual rotation angle of the rotor 2.

[0037] In the second step S2, the second calculation unit 11 determines the actual rotation angle of the rotor 2 based on the data detected by the rotation angle sensor 9. In step S2, the determined actual rotation angle In addition, it is provided to the first computing unit 10.

[0038] In the third step S3, the first calculation unit 10 calculates the actual rotation angle. To determine the actual rotational speed of rotor 2. Alternatively, step S3 can preferably be omitted here. In this case, the actual rotational speed has preferably already been determined by the second calculation unit 11 in step S2, and the actual rotational speed determined by the second calculation unit 11 is provided to the first calculation unit 10.

[0039] In step S4, the first calculation unit 10 calculates the rotor 2 based on its rated speed RPM. Soll The value of the rated voltage vector |U| is determined based on the actual rotational speed of rotor 2. Furthermore, in step S4, the determined value |U| is provided to the second calculation unit 11.

[0040] In step S5, the second calculation unit 11 calculates the value |U| and the actual rotation angle. To determine the control signal used to control the switching element of the power electronic device 7.

[0041] In step S6, the switching elements of the power electronic device 7 are finally controlled according to the determined control signal, so that phases U, V and W are electrically connected to or electrically disconnected from the energy storage device 6 through the switching elements.

[0042] Preferably, steps S1 to S6 are executed continuously. This results in advantageous regulation of the energization of phases U, V, and W by means of the control device 8. Because the first calculation unit 10 has a longer cycle time compared to the second calculation unit 11, the time interval between the values ​​|U| that are directly determined in time for the rated voltage vector is greater than the time interval between the control signals that are directly determined in time for the power electronics 7.

Claims

1. A control device for operating an electric motor, wherein the electric motor (1) has a rotor (2), a stator (4), and power electronics (7), wherein the rotor (2) is arranged in an anti-rotation manner on a shaft (3) rotatably mounted in a housing, wherein the stator (4) is arranged in a manner fixed relative to the housing and has stator windings (5) having at least three phases (U, V, W), wherein the power electronics (7) has a plurality of switching elements, through which the phases (U, V, W) are electrically connected / possibly electrically connected to an energy storage device (6), and wherein the control device (8) has a first computing unit (10) and a second computing unit (11), and wherein the control device (8) is configured to determine, by means of the first and second computing units (10, 11), control signals for controlling the switching elements, characterized in that, The first calculation unit (10) is configured to calculate based on the rated speed (RPM) of the rotor (2). Soll The actual rotational speed of the rotor (2) determines the value of the rated voltage vector for the phases (U, V, W). The second computing unit (11) is connected to the first computing unit (10) via communication technology, and the second computing unit (11) is configured to calculate the value of the rated voltage vector according to the value of the rated voltage vector. ) and the actual rotation angle of the rotor (2) The orientation of the rated voltage vector and / or the individual rated phase voltages are determined, and the control signal is determined based on the determined rated phase voltages. The control device has a device (16) that can be connected to the angle sensor (9) of the motor (1) via communication technology, wherein the second calculation unit (11) is configured to determine the actual angle based on data received by means of the device (16). ), The control device (8) is configured as a microcontroller (8). The first computing unit (10) is the main computing unit (10) of the microcontroller (8). The second computing unit (11) is an auxiliary computing unit of the microcontroller (8), and The first computing unit (10) has a first cycle time, and the second computing unit (11) has a second cycle time, wherein the second cycle time is shorter than the first cycle time.

2. The control device according to claim 1, characterized in that, The second computing unit (11) is the timer of the microcontroller (8).

3. The control device according to claim 1, characterized in that, The first calculation unit (10) is configured to determine at least one permissible maximum phase current (I Max ), and pre-determine the maximum phase current (I) for the second calculation unit (11). Max ), wherein the second calculation unit (11) is configured to calculate based on the maximum phase current (I Max The control signal is determined by the control signal.

4. The control device according to any one of claims 1-3, characterized in that, The first calculation unit (10) is configured to determine at least one rated commutation angle ( And the second calculation unit (11) is given a predetermined rated commutation angle in advance. ), wherein the second calculation unit (11) is configured according to the rated commutation angle ( The control signal is determined by the control signal.

5. An electric motor (1) having a rotor (2), a stator (4), and power electronics (7), wherein the rotor (2) is arranged in an anti-rotation manner on a shaft (3) rotatably mounted in a housing, wherein the stator (4) is arranged in a manner fixed relative to the housing and has stator windings (5) having at least three phases (U, V, W), and wherein the power electronics (7) has a plurality of switching elements through which the phases (U, V, W) are electrically connected / can be electrically connected to an energy storage device (6), characterized in that The control device (8) according to any one of claims 1 to 4.

6. The motor according to claim 5, characterized in that... Used to monitor the actual rotation angle of the rotor (2) ) Angle sensor (9).

7. A method for operating an electric motor (1), the electric motor (1) having a rotor (2), a stator (4), power electronics (7), and a control device (8), wherein the rotor (2) is arranged in an anti-rotation manner on a shaft (3) rotatably mounted in a housing, wherein the stator (4) is arranged in a manner fixed relative to the housing and has stator windings (5) having at least three phases (U, V, W), wherein the power electronics (7) has a plurality of switching elements, wherein the control device (8) determines control signals for controlling the switching elements, and wherein the switching elements are controlled according to the control signals such that the phases (U, V, W) are selectively electrically connected to or electrically disconnected from an energy storage device (6) via the switching elements; characterized in that, According to the rated speed (RPM) for the rotor (2) Soll The actual rotational speed of the rotor (2) and the first calculation unit (10) of the control device (8) determine the value of the rated voltage vector for the phases (U, V, W). ); According to the value of the rated voltage vector ( ) and the actual rotation angle of the rotor (2) The orientation of the rated voltage vector and / or the individual rated phase voltages are determined by a second computing unit (11) of the control device (8) which is connected to the first computing unit (10) via communication technology, and the control signal is determined based on the determined rated phase voltages; and The device (16) is connected to the angle sensor (9) of the motor (1) via communication technology, wherein the second calculation unit (11) determines the actual angle based on the data received by means of the device (16). ), The control device (8) is configured as a microcontroller (8). The first computing unit (10) is the main computing unit (10) of the microcontroller (8). The second computing unit (11) is an auxiliary computing unit of the microcontroller (8). The first computing unit (10) has a first cycle time, and the second computing unit (11) has a second cycle time. The second cycle time is shorter than the first cycle time.

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