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EP-4736311-A1 - FREQUENCY CONVERTER AND DRIVE SYSTEM

EP4736311A1EP 4736311 A1EP4736311 A1EP 4736311A1EP-4736311-A1

Abstract

The invention relates to a frequency converter (1) for actuating an electric motor (2), comprising: - sensor elements (3 to 8), which are designed to generate sensor data (x1 to xn), and - a control unit (9), which is designed to control the operation of the frequency converter (1) depending on the sensor data (x1 to xn), - wherein the control unit (9) is designed to calculate at least one feature (y1 to ym) from the sensor data (x1 to xn).

Inventors

  • KÜHN, Johannes

Assignees

  • Lenze SE

Dates

Publication Date
20260506
Application Date
20240628

Claims (11)

  1. 1. Frequency converter (1) for controlling an electric motor (2), comprising: sensor elements (3 to 8) which are designed to generate sensor data (x1 to xn), and a control unit (9) which is designed to control the operation of the frequency converter (1) depending on the sensor data (x1 to xn), characterized in that the control unit (9) is designed to calculate at least one feature (y1 to ym) from the sensor data (x1 to xn).
  2. 2. Frequency converter (1) according to claim 1, characterized in that the at least one feature (y1 to ym) is provided to form an input variable of a Kl unit (10) separate from the frequency converter.
  3. 3. Frequency converter (1) according to one of the preceding claims, characterized in that the frequency converter (1) has at least one of the following sensor elements: a current sensor (3) for detecting a drive current, a speed sensor (4) for detecting a motor speed, a position sensor (5) for detecting a load position, a sensor (6) for detecting an operating time of the frequency converter (1), a voltage sensor (7) for detecting a drive voltage, a temperature sensor (8) for detecting an operating temperature of the frequency converter (1), and a temperature sensor connection for connecting an external temperature sensor, in particular a motor temperature sensor.
  4. 4. Frequency converter (1) according to claim 3, characterized in that the control unit (9) is designed to calculate at least one of the following features (y1 to ym) from the sensor data: a frequency spectrum of the drive current, and/or a frequency spectrum of the motor speed, and/or a frequency spectrum of the load position, and/or a frequency spectrum of a lag error, an average torque generated by the electric motor (2), and/or an average motor speed, and/or an average electrical or mechanical power, a variance of the torque generated by the electric motor (2), and/or a variance of the engine speed, a number of operating hours, and/or a number of engine revolutions at a torque that is greater than a threshold torque, and a maximum speed, and/or a maximum torque generated by the electric motor (2), and/or a maximum electrical power, and/or a maximum operating temperature, and/or a maximum drag error.
  5. 5. Frequency converter (1) according to one of the preceding claims, characterized in that the control unit (9) is designed to calculate the at least one feature (y1 to ym) discontinuously from the sensor data (x1 to xn).
  6. 6. Frequency converter (1) according to one of the preceding claims, characterized in that the control unit (9) is designed to calculate the at least one feature (y1 to ym) from the sensor data (x1 to xn) only as long as the frequency converter (1) controls the electric motor (2) to execute a predetermined test drive profile.
  7. 7. Frequency converter (1) according to claim 6, characterized in that the predetermined test drive profile consists of a predetermined sequence of accelerations and movements at constant speed.
  8. 8. Frequency converter (1) according to one of the preceding claims, characterized in that the control unit (9) is designed to calculate the at least one feature (y1 to ym) exclusively from sensor data (x1 to xn) relating to a torque generated by means of the electric motor (2).
  9. 9. Frequency converter (1) according to one of the preceding claims, characterized in that the control unit (9) is designed to calculate the at least one feature (y1 to ym) exclusively from selected sensor data (x1 to xn), wherein operating parameter values, in particular in the form of position values, speed values and torque values, lie within specified limits for the selected sensor data (x1 to xn).
  10. 10. Drive system (100), comprising: a frequency converter (1) according to one of the preceding claims, and a Kl unit (10) formed separately from the frequency converter (1), wherein the at least one feature (y1 to ym) generated by means of the frequency converter (1) is provided to form an input variable of the Kl unit (10).
  11. 11. Drive system (100) according to claim 10, characterized in that the Kl unit (10) is designed to determine a state (Z1 to Zk) of the drive system (100) based on the at least one feature.

Description

frequency converter and drive system The invention is based on the object of providing a frequency converter and a drive system that enable a statement about their condition to be made as reliably as possible. The frequency converter is used to control an electric motor. The frequency converter has conventional sensor elements or sensors that are designed to generate sensor data. The frequency converter also has a control unit, for example in the form of a microprocessor-based controller, which is designed to control the operation of the frequency converter depending on the sensor data. The control unit is designed to calculate at least one feature from the sensor data. A feature is in particular a scalar value that is obtained from the sensor data and characterizes it. For example, a feature is a maximum value, a minimum value, a temporal average, an energy within certain frequency bands, etc. of the sensor data. In one embodiment, the at least one feature forms an input variable of an artificial intelligence (AI) unit separate from the frequency converter. In one embodiment, the frequency converter has at least one, in particular all, of the following sensor elements: a current sensor for detecting a drive current output by the frequency converter, a speed sensor for detecting a motor speed of an electric motor controlled by the frequency converter, a position sensor for detecting a position of a mechanical load moved by the electric motor, a sensor for detecting an operating time of the frequency converter, a voltage sensor for detecting a drive voltage generated by the frequency converter, a temperature sensor for detecting an operating temperature of the frequency converter, and a temperature sensor connection for connecting an external temperature sensor, in particular a motor temperature sensor. In one embodiment, the control unit is designed to calculate at least one, in particular all, of the following features from the sensor data: a frequency spectrum of the drive current, and/or a frequency spectrum of the engine speed, and/or a frequency spectrum of the load position, and/or a frequency spectrum of a lag error, and/or an average torque generated by the electric motor, and/or an average engine speed, and/or an average electrical or mechanical power, and/or a variance of the torque generated by the electric motor, and/or a variance of the engine speed, a number of operating hours, and/or a number of engine revolutions. rotations at a torque greater than a threshold torque, and/or a maximum speed, and/or a maximum torque generated by the electric motor, and/or a maximum electrical power, and/or a maximum operating temperature, and/or a maximum following error. In one embodiment, the control unit is designed to calculate the at least one feature from the sensor data discontinuously over time, i.e. not to calculate it continuously or continuously. This makes it possible to generate small amounts of data with a high information content, since the at least one feature is only generated when characteristic and meaningful conditions exist. During other periods, no calculation takes place, so that the calculation effort and the data volume can be minimized. In one embodiment, the control unit is designed to calculate the at least one feature from the sensor data only in time intervals during which the frequency converter controls the electric motor to execute a predetermined test drive profile or measurement profile. The at least one feature is therefore determined exclusively under comparable or identical conditions. In one embodiment, the predefined test driving profile consists of a predefined sequence of accelerations and movements at a constant speed. For example, the predefined test driving profile can be composed as follows: from a standstill, the vehicle accelerates to a maximum speed, the maximum speed is kept constant for a predefined period of time, and then the vehicle brakes again to a standstill. In one embodiment, the control unit is designed to calculate the at least one feature exclusively from sensor data relating to a torque generated by the electric motor. According to the invention, it was recognized that the torque is highly characteristic of the state of the electric drive system, so that it may be sufficient to evaluate only the torque. In one embodiment, the control unit is designed to calculate the at least one feature only from sensor data for which previously defined criteria are met, which ensure the information content and comparability. Typical criteria for the selection can be that the speed during the measurement is in a defined range, or that the torque permanently exceeds a minimum value. The drive system has a frequency converter described above and a Kl unit formed separately from the frequency converter, wherein the at least one feature generated by means of the frequency converter is intended to form an input variable of the Kl unit. In one embodiment, the Kl unit