DRIVE DEVICE FOR USE IN A LABORATORY DEVICE

• US 20110243793A1
• Filed: 04/05/2011
• Published: 10/06/2011
• Est. Priority Date: 04/06/2010
• Status: Active Grant

• Current Assignee: Tecan Trading AG (Tecan Group AG)
• Original Assignee: Tecan Trading AG (Tecan Group AG)
• Inventors: Kälin, Remo
• Granted Patent: US 9,263,981 B2
• Time in Patent Office: Days
• US Class Current: 422/67
• CPC Class Codes: H02P 21/06 Rotor flux based control involving the use of rotor position or rotor speed sensors
• CPC Class Codes: H02P 8/14 Arrangements for controlling speed or speed and torque H02P8/12, H02P8/22 take precedence

Abstract

The invention relates to a drive device (100) for use in a laboratory device, having a stepping motor (10) having rotor and stator, and having a motor controller (20), which is designed for the purpose of activating the stepping motor (10). In one embodiment, the drive device (100) comprises an encoder (11), which supplies a respective current encoder signal (e(t)) in operation (ia, ib), which reflects the current rotor position of the rotor, and phase terminals (14, 27), to tap the currently flowing motor phase currents (ia, ib). The motor controller (20) comprises a transformation module (13), in order to decompose the currently flowing motor phase currents (ia, ib) using a transformation method into a slip component (ix) and a torque component (iy). Furthermore, it comprises a slip regulation module (15), to which the slip component (ix) and a first target value (ix*) are supplied as input variables, and a torque regulation module (16), to which the torque component (iy) and a second target value (iy*) are supplied as input variables. The slip regulation module (15) and the torque regulation module (16) predefine the rotor phase currents (ia, ib) so that the difference between the slip component (ix) and the first target value (ix*) and the difference between the torque component (iy) and the second target value (iy*) are minimal.

Claims

1. :

A drive device for use in a laboratory device, having

a motor with rotor and stator, and having

a motor controller, arranged for controlling the motor, wherein the drive device comprises;

position acquisition means, which in operation supplies in each case a current signal, which indicates the current rotor position of the rotor,

phase terminals, to tap the currently flowing motor phase currents on the motor side, and

wherein the motor controller comprises;

a transformation module, to decompose the currently flowing motor phase currents into a slip component and a torque component using a transformation method,

a slip regulation module, to which the slip component and a first target value are provided as input variables,

a torque regulation module, to which the torque component (iy) and a second target value are provided as input variables,

wherein the slip regulation module and the torque regulation module predefine the rotor phase currents for commutation of the motor so that the difference between the slip component and the first target value and the difference between the torque component and the second target value are minimal.

2. The drive device according to claim 1, wherein an encoder acts as the position acquisition means, wherein the encoder is assigned to the motor, and wherein the current signal is an encoder signal.

3. The drive device according to claim 1, wherein the motor is an encoder-free motor, which is briefly operable in generator operation in order to supply a generator signal in generator operation, by utilizing the back-EMF effect as the current signal.

4. The drive device according to claim 1, or 2, or 3, wherein the motor controller comprises an inverting transformer and a pulse-width modulation module, in order to transform output signals of the slip regulation module and the torque regulation module into control variables, which can be converted by the pulse-width modulation module into the motor phase currents.

5. The drive device according to claim 1, wherein the transformation module comprises a matrix transformer.

6. The drive device according to claim 5, wherein the matrix transformer generates the slip component and the torque component from current values using a matrix transformation.

7. The drive device according to claim 1, wherein the motor phase currents can be modulated by the motor controller and the current motor phase currents are dependent on the difference between the slip component and the first target value and the difference between the torque component and the second target value respectively.

8. The drive device according to claim 1, wherein the motor phase currents can be regulated to zero by the motor controller, if no external forces are applied to the motor.

9. The drive device according to claim 1, or 2, or 3, or 8, wherein an actual position can be ascertained using a position regulation module on the basis of the current signal, and the torque of the motor is settable so that the difference between the target position and the actual position is minimal.

10. The drive device according to claim 1 or 8, wherein the slip component and the torque component can be regulated individually and independently of one another using the motor controller.

11. The drive device according to claim 1, wherein low-pass and magnetic flux properties of the motor can be compensated for using the motor controller, in order to thus be able to predefine a speed-independent torque of the stepping motor.

12. The drive device according to claim 1, wherein the motor controller comprises an integrated circuit, preferably a digital signal processor (DSP), in which at least one of the following regulation modules

slip regulation module,

torque regulation module,

position regulation module,

module for encoder signal processing, or

module for generator signal processing is implemented.

13. The drive device according to claim 1 or 8, wherein the motor controller is a pump controller and the motor is a pump motor.

14. The drive device according to claim 1 or 8, wherein the rotor of the motor is mechanically connected to a moving pump element, preferably a pump piston, a spindle shaft, a gearwheel, a toothed roller or a toothed wheel, or a tappet of a pump.

15. The drive device according to claim 8 or 11, wherein the laboratory device is a diluter, and the drive device is designed for installation in the diluter.

16. A laboratory device having at least one drive device according to claim 1, or 2, or 3 or 5, or 6, or 7, or 8, or 11 or 12, wherein the laboratory device is technically controllably connected with respect to control to the motor controller.

17. A method for controlling a motor having the following steps:

providing a current signal, which represents position information about the rotor position of the motor,

tapping phase currents of the motor,

predefining a first target value to regulate a slip component,

predefining a second target value to regulate a torque component,

predefining a commutation of the motor, wherein the slip component and the torque component are regulated independently of one another so that, due to the commutation, a stator field of the motor is built up by the corresponding phase currents.

18. The method according to claim 17, wherein the phase currents are dynamically set so that the difference between the slip component and the first target value and the difference between the torque component and the second target value are minimal.

19. The method according to claim 17 or 18, wherein the phase currents are dynamically regulated depending on load and behave proportionally to a currently applied torque component.

20. The method according to claims 17 or 18, wherein in an initialization step, the mechanical rotational angle of the motor is synchronized with the electrical field which is applied to the motor by the commutation.

21. The method according to claim 20, wherein in the initialization step during an initialization movement, the current signal is input and brought into relation with a control signal, in order to calculate the zero position on the basis of the relation between the current signal, and the control signal.