Control device for actuating an electric motor, electric motor and system having a control device and electric motor

Abstract

A control device for actuating an electric motor has: a temperature sensor interface for connecting an external temperature sensor, wherein the temperature sensor is provided to monitor the temperature of the electric motor, and a monitoring unit, which is configured to evaluate at least one temperature-dependent property of the temperature sensor in order to monitor the temperature of the electric motor and to exchange data with the electric motor via the temperature sensor interface independently of and in addition to the temperature monitoring.

Claims

1. A control device for actuating an electric motor, comprising: a temperature sensor interface for connecting an external temperature sensor, wherein the external temperature sensor is provided to monitor temperature of the electric motor; and a monitoring unit, which is configured to evaluate at least one temperature-dependent property of the temperature sensor in order to monitor the temperature of the electric motor, wherein the monitoring unit is further configured to exchange data with the electric motor via the temperature sensor interface independently of and in addition to the temperature monitoring.

2. The control device according to claim 1, wherein the monitoring unit is configured to output a voltage or a current at the temperature sensor interface.

3. The control device according to claim 2, wherein the monitoring unit is configured to evaluate an electrical resistance of the temperature sensor in order to monitor the temperature of the electric motor.

4. The control device according to claim 1, wherein the monitoring unit is configured to evaluate an electrical resistance of the temperature sensor in order to monitor the temperature of the electric motor.

5. The control device according to claim 1, wherein the monitoring unit is configured to output a prescribed pulse pattern at the temperature sensor interface in order to initiate a data exchange with the electric motor.

6. The control device according to claim 1, wherein the monitoring unit is configured to evaluate a signal profile produced at the temperature sensor interface for decoding data transmitted from the electric motor to the control device.

7. The control device according to claim 1, wherein the temperature sensor interface is a two-conductor interface.

8. The control device according to claim 1, further comprising: a motor actuating interface for connecting phase sections of the electric motor.

9. An electric motor, comprising: a temperature monitoring interface; and a temperature sensor that is connected to the temperature monitoring interface, wherein the electric motor comprises: a control unit, which is connected to the temperature monitoring interface and which is configured to exchange data with a control device via the temperature monitoring interface independently of and in addition to the temperature monitoring.

10. The electric motor according to claim 9, wherein the control unit is supplied with electrical operating energy via the temperature monitoring interface.

11. The electric motor according to 9, wherein the electric motor has a switch that is actuated by the control unit, wherein the switch and the temperature sensor are looped in in series between connection poles of the temperature monitoring interface, and the control unit is configured to close the switch in a temperature measuring mode and to open the switch in a data transmission mode.

12. The electric motor according to claim 9, wherein the temperature sensor is a temperature-dependent resistor or a thermal contact.

13. The electric motor according to claim 9, wherein the electric motor has a memory, a content of which is readable out and/or writable to via the temperature monitoring interface.

14. The electric motor according to claim 13, wherein information that characterizes properties of the electric motor is stored in the memory.

15. A system, comprising: (i) an electric motor comprising: a temperature monitoring interface; a temperature sensor that is connected to the temperature monitoring interface; and a motor control unit, which is connected to the temperature monitoring interface and which is configured to exchange data via the temperature monitoring interface; and (ii) a control device comprising: a temperature sensor interface for connecting the temperature sensor, wherein the temperature sensor is provided to monitor temperature of the electric motor; and a monitoring unit, which is configured to evaluate at least one temperature-dependent property of the temperature sensor in order to monitor the temperature of the electric motor, wherein the monitoring unit is further configured to exchange data with the electric motor via the temperature sensor interface independently of and in addition to the temperature monitoring.

16. The system according to claim 15, wherein the control device is configured to read out a memory of the electric motor and to actuate the electric motor depending on data read out from the memory.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described below in detail with reference to the drawing, in which:

(2) FIG. 1 shows a system having a control device and an electric motor that is actuated by means of the control device.

DETAILED DESCRIPTION OF THE DRAWINGS

(3) FIG. 1 shows a system having a control device 1 in the form of a frequency converter and a three-phase motor 2, which is actuated by means of the control device 1. For this purpose, the control device 1 conventionally has a motor actuating interface 6 for connecting phase sections u, v, w of the electric motor 2. In this respect, reference should also be made to the relevant technical literature.

(4) The control device 1 further has a temperature sensor interface 3 for connecting a temperature sensor 4 in the form of a PTC thermistor or thermal contact arranged in the electric motor 2. The temperature sensor 4 conventionally serves to monitor the temperature of the electric motor 2.

(5) In a manner corresponding to the temperature sensor interface 3 of the control device 1, the electric motor 2 has a temperature monitoring interface 7, wherein a semiconductor switch 9 and the temperature sensor 4 are looped in in series between connection poles 7a, 7b of the temperature monitoring interface 7. The interfaces 3 and 7 are each two-conductor interfaces.

(6) The temperature sensor interface 3 of the control device 1 and the temperature monitoring interface 7 of the electric motor 2 are electrically connected to one another by means of associated cores of a multicore connection cable 11. Corresponding cores of the connection cable 11 further serve to electrically connect the motor actuating interface 6 of the control device 1 to the phase sections u, v, w of the electric motor 2.

(7) The control device 1 further has a monitoring unit 5, which is configured to conventionally evaluate a resistance of the temperature sensor 4 in order to monitor the temperature of the electric motor 2.

(8) The monitoring unit 5 is further configured to exchange data with the electric motor 2 via the temperature sensor interface 3 independently of and in addition to the temperature monitoring, which will be described in more detail below.

(9) In order to be able to exchange data in a bidirectional manner with the control device 1, the electric motor 2 has a control unit 8, which is likewise connected to the temperature monitoring interface 7 and which is configured to exchange data in a bidirectional manner with the control device 1 via the temperature monitoring interface 7. To this end, the control unit 8 actuates the semiconductor switch 9 in such a way that it is closed in a temperature measuring mode and is open in a data transmission mode.

(10) The monitoring unit 5 of the control device 1 outputs a voltage that serves to supply voltage to the control unit 8 at the temperature sensor interface 3 as long as the switch 9 is open.

(11) A switch-on of the system 1 is described below.

(12) After the control device 1 has been supplied with energy, the control device 1 starts up and outputs a voltage, for example at a level of 3.3 V, at the temperature sensor interface 3 thereof. The output that drives the temperature sensor interface 3 may be, for example, an open-drain output or an open-collector output.

(13) When the switch 9 is open, said voltage charges a buffer capacitor 12 of the electric motor 2 by means of a decoupling diode 13, wherein the control unit 8 is supplied with energy from the buffer capacitor 12. As soon as a voltage level produced at the capacitor 12 is sufficient to supply power to the control unit 8, the control unit 8 continually checks a voltage profile at the temperature monitoring interface 7.

(14) In order to initiate a data exchange with the electric motor 2 or the control unit 8 thereof, the monitoring unit 5 generates a defined voltage pulse pattern at the temperature sensor interface 3 for a prescribed period. Said voltage pulse pattern is identified by the control unit 8 and used to synchronize or initiate the data transmission.

(15) For the transmission of data from the control unit 8 in the direction of the monitoring unit 5, the control unit 8 has a semiconductor switching element, which is not illustrated, wherein for example approximately 3.3 V are produced at the temperature sensor interface 3 in the open state of said semiconductor switching element and approximately 0 V is produced in the closed state of the semiconductor switching element, with the result that the control unit 8 can generate by means of the semiconductor switching element a pulse sequence that serves to encode the data that is to be transmitted.

(16) For the transmission of data from the monitoring unit 5 in the direction of the control unit 8, the monitoring unit 5 generates a suitable voltage pulse pattern at the temperature sensor interface 3 to encode the data that is to be transmitted.

(17) After all of the necessary data has been transmitted between the control device 1 or the monitoring unit 5 and the control unit 8, the control unit 8 closes the switch 9, as a result of which said control unit itself is switched off and only the temperature sensor 4 remains visible between the connection poles 7a and 7b.

(18) When the control device 1 does not generate the defined voltage pulse pattern at the temperature sensor interface 3 for initiating the data transmission after start-up within the prescribed period, the control unit 8 closes the switch 9, as a result of which said control unit itself is switched off and only the temperature sensor 4 remains visible between the connection poles 7a and 7b. Therefore, the electric motor 2 according to the invention is also able to be used with conventional control devices that do not have the option of data transmission via their temperature sensor interface 3.

(19) When a control device 1 according to the invention is used with a conventional electric motor that does not have the option of data transmission via its temperature monitoring interface 7, the control device 1 identifies this from the fact that no reaction to the temperature sensor interface 3 is received after the initiation of the data transmission. The control device 1 according to the invention is therefore also able to be used with conventional electric motors that do not have the option of data transmission via their temperature monitoring interface 7.

(20) The electric motor 2 has a non-volatile memory 10, the content of which can be read out and/or can be written to via the temperature monitoring interface 7. Information that characterizes the properties of the electric motor 2 is stored in the memory 10. In addition, a serial number, an operating hours counter, etc. can be stored in the memory 10.

(21) The control device 1 is configured to at least partly read out the memory 10 of the electric motor 2 and to actuate the electric motor 2 depending on the data read out.

(22) For example, a rated power, a current carrying capacity, electrical parameters, etc. that influence the actuation voltages/actuation currents generated by the control device 1 can be stored in the memory 10.