System comprising an externally excited synchronous machine

Abstract

The invention relates to a system (100), comprising: - an externally excited synchronous machine (1), - a rotary encoder (2, 3, 4) which determines a rotational angle position of an output shaft (6) of the externally excited synchronous machine (1), - an, in particular stator-mounted, control electronics system which is designed to control an excitation current in rotor coils (17) for generating an excitation field to a predefinable target value, and - a connection (8) for a data transmission bus, via which both data relating to the determined rotational angle position are transmitted and data relating to control parameters of the control electronics system are transmitted.

Description

[0001] System with a separately excited synchronous machine

[0002] The invention is based on the objective of providing a system with a separately excited synchronous machine that is as easy to operate as possible.

[0003] The system according to the invention comprises a separately excited synchronous machine, i.e., an electric motor in which the magnetic rotor field is generated by a current flowing through coils in the rotor. For further information, reference is made to the relevant technical literature.

[0004] The system according to the invention further comprises a rotary encoder that determines the angular position of an output shaft of the separately excited synchronous machine. The rotary encoder can, for example, be a resolver, encoder, etc.

[0005] The system according to the invention further comprises control electronics, in particular attached to the stator, which are designed to regulate an excitation current in rotor coils to a predefinable setpoint for generating an excitation field in or of the rotor.

[0006] The system according to the invention further has a connection for a data transmission bus, in particular a bidirectional one, for example for an EtherCAT data transmission bus, via which data relating to the determined rotation angle position is transmitted to a receiver and data relating to control parameters of the control electronics are received.

[0007] In one embodiment, electrical power for generating the excitation field is transferred contactlessly towards the rotor of the separately excited synchronous machine, for example by means of a transformer.

[0008] In one embodiment, the system further comprises a circuit board that can be electrically and mechanically coupled to the separately excited synchronous machine. In this case, the rotary encoder has a rotary encoder body mounted on the circuit board and a number of rotary encoder sensors mechanically held within the rotary encoder body. The rotary encoder further comprises an anisotropic sensor body that can be rotationally coupled to the output shaft of the separately excited synchronous machine. When the output shaft rotates, this anisotropic sensor body generates angle-specific signals in the rotary encoder sensors. The rotary encoder also includes an evaluation unit mounted on the circuit board, which determines the angular position based on the signals from the rotary encoder sensors. The control electronics are also mounted on the circuit board. The connection for the data transmission bus, for example in the form of a connector, is also mounted on the circuit board.

[0009] In one embodiment, the system has a stator voltage connection arranged on the circuit board for connecting, in particular, three stator voltages for one stator of the separately excited synchronous machine. One or more of the stator voltages can also be supplied to the control electronics so that they can generate a desired excitation current from the stator voltage(s).

[0010] In one embodiment, the system has a number of electrical motor contacts, for example between two and 40 motor contacts, arranged on the circuit board. At least one motor contact is electrically connected via conductor tracks on the circuit board to a corresponding stator voltage terminal. The electrical motor contacts are designed to electrically connect corresponding terminals of the stator when the circuit board is placed on the separately excited synchronous machine, so that the stator windings can be supplied with the appropriate voltages.

[0011] In one embodiment, the stator voltage connection is designed as a connector.

[0012] In one embodiment, the connection for the data transmission bus is designed as a connector.

[0013] In permanent magnet synchronous machines, the excitation field is generated by permanent magnets. These are expensive and subject to significant price fluctuations. When operating at speeds high compared to the rated speed, they are in the so-called field weakening range. In this range, the stator field actively reduces the field in the rotor, significantly decreasing efficiency and greatly increasing losses.

[0014] Externally excited synchronous machines can avoid the problems mentioned above. Since this type of machine requires different frequency converters than those commonly used on the market, they are rarely used widely.

[0015] By integrating the control electronics or excitation current control electronics into the motor or the separately excited synchronous machine according to the invention, this problem can be circumvented, since from the perspective of a frequency converter, the separately excited synchronous machine then essentially behaves like a permanent magnet synchronous machine. The control electronics or excitation current control electronics are preferably controlled via a data bus, which is also used for a rotary encoder that is normally already present. Both the rotary encoder data and the field control data can be transmitted simultaneously via the same data bus.

[0016] The separately excited synchronous machine is more economical than a permanent magnet motor. At the same time, losses during field weakening operation can be significantly reduced by controlling the excitation field or the rotor field.

[0017] The invention relates to, or is, a separately excited synchronous machine with integrated excitation current control with transmission of the encoder data and control data via the same data bus.

[0018] The invention is described in detail below with reference to the drawings. [The following is shown.]

[0019] Fig. 1 schematically shows a section through a system according to the invention and

[0020] Fig. 2 schematically shows a top view of a printed circuit board of the device shown in Fig. 1.

[0021] Systems on which a multitude of system functionalities are integrated.

[0022] Fig. 1 shows a highly schematic longitudinal section through a system 100 according to the invention. The system 100 comprises a, in particular conventional, separately excited synchronous machine 1 with a stator 15, a rotor 9 and an output shaft 6 coupled to the rotor in a rotationally fixed manner. In this respect, reference is also made to the relevant technical literature on separately excited synchronous machines.

[0023] The system 100 further includes a rotary encoder 2, 3, 4, 5, see also Fig. 2, which determines a rotational angle position of the output shaft 6 of the separately excited synchronous machine 1.

[0024] The system 100 further includes a stator-fixed control electronics 7, see Fig. 2, which is designed to control an excitation current for coils 17 of the rotor 9 to generate an excitation field to a predefinable setpoint.

[0025] The system 100 further features a connection 8 for a data transmission bus, via which data relating to the determined rotation angle position is transmitted as well as data relating to control parameters of the control electronics 7, for example a setpoint for the excitation current, a phase angle of the excitation current, etc.

[0026] Electrical power for generating the excitation field is conventionally transferred by transformer in the direction of the rotor 9 of the separately excited synchronous machine 1.

[0027] Figs. 1 and 2 show a circuit board 10 that can be electrically and mechanically coupled to the separately excited synchronous machine 1.

[0028] The rotary encoder comprises: a rotary encoder body 3 arranged on the circuit board 10, a number of rotary encoder sensors in the form of coil windings 4 which are held in the rotary encoder body 3, an anisotropic sensor body 2 which can be coupled to the output shaft 6 of the separately excited synchronous machine 1 in a rotationally fixed manner and an evaluation unit 5 arranged on the circuit board 10 which determines the rotational angle position based on signals from the rotary encoder sensors 4.

[0029] The control electronics 7, the connection 8 for the data transmission bus and a stator voltage connection 11 for connecting stator voltages for the stator 15 of the separately excited synchronous machine 1 are also arranged on the circuit board 10.

[0030] Furthermore, a number of electrical motor contacts 12 are arranged on the circuit board 10, for example between 2 and 24 motor contacts 12, wherein at least one motor contact 12 is electrically connected by means of conductor tracks 13 on the circuit board 10 to a corresponding stator voltage connection contact 14 of the stator voltage connection 11. The electrical motor contacts 12 are designed to electrically contact corresponding terminals 16 of the stator 15 when the circuit board 10 is placed on the separately excited synchronous machine 1 as intended (see Fig. 1), and thus supply the stator 15 with the corresponding stator voltages.

[0031] The connection 8 for the data transmission bus and the stator voltage connection 11 are each designed as connectors.

Claims

Patent claims 1. System (100) comprising: a separately excited synchronous machine (1), a rotary encoder (2, 3, 4, 5) which determines a rotational angular position of an output shaft (6) of the separately excited synchronous machine (1), a control electronics unit (7), in particular stator-mounted, which is configured to control an excitation current in rotor coils (17) to generate an excitation field to a predefinable setpoint, and a connection (8) for a data transmission bus, via which both data relating to the determined rotational angular position and data relating to control parameters of the control electronics unit (7) are transmitted.

2. System (100) according to claim 1 , characterized in that electrical power for generating the excitation field is transferred without contact in the direction of the rotor (9) of the separately excited synchronous machine (1 ).

3. System (100) according to one of the preceding claims, further comprising: a printed circuit board (10) electrically and mechanically coupling to the separately excited synchronous machine (1), wherein the rotary encoder comprises: a rotary encoder base body (3) arranged on the printed circuit board (10), a number of rotary encoder sensors (4) held in the rotary encoder base body (3), an anisotropic sensor body (2) rotationally fixed to the output shaft (6) of the separately excited synchronous machine (1), and an evaluation unit (5) arranged on the printed circuit board (10) which determines the angular position based on signals from the rotary encoder sensors (4), wherein the control electronics (7) are arranged on the printed circuit board (10) and wherein the connection (8) for the data transmission bus is arranged on the printed circuit board (10).

4. System (100) according to claim 3, further comprising: a stator voltage connection (11) arranged on the circuit board (10) for connecting stator voltages for a stator (15) of the separately excited synchronous machine (1).

5. System (100) according to claim 4, further comprising: a number of electrical motor contacts (12) arranged on the circuit board (10), wherein at least one motor contact (12) is electrically connected by means of conductor tracks (13) on the circuit board (10) to an associated stator voltage connection contact (14) of the stator voltage connection (11), and wherein the electrical motor contacts (12) are provided to electrically contact corresponding terminals (16) of the stator (15) when the circuit board (10) is placed on the separately excited synchronous machine (1) as intended.

6. System (100) according to one of the preceding claims, characterized in that the stator voltage connection (11 ) is designed as a connector.

7. System (100) according to one of the preceding claims, characterized in that the connection (8) for the data transmission bus is designed as a connector.

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