Synchronous machine and method for regulating the rotational speed of the synchronous machine without sensors

Abstract

A permanent magnet synchronous machine (1) having a rotor (R) and a stator (S). Connection terminals (2) apply a feed alternating voltage with a feed frequency (f.sub.0). The permanent magnet synchronous machine (1) has a motor controller (10). The controller (10) has an assembly (11) to detect the terminal voltage on the connection terminals (2) and the current frequency (f.sub.a). Also, the controller has an analysis device (12). The analysis device (12) ascertains whether the current frequency (f.sub.a) contains a frequency component (f.sub.r) with a frequency that deviates from the feed frequency (f.sub.0).

Claims

1. A permanent magnet synchronous machine comprising: a rotor (R) and a stator (S) formed with connection terminals for applying a feed alternating voltage with a feed frequency (f.sub.0); a motor controller including: an assembly for detecting the terminal current on the connection terminals and a current frequency (f.sub.a) of the terminal current; and an analysis device, the analysis device configured to ascertain whether the current frequency (f.sub.a) contains a frequency component (f.sub.r) with a frequency that deviates from the feed frequency (f.sub.0), and whether the frequency component (f.sub.r) is a decreasing frequency; and the motor controller is configured to, as a function of the determined frequency component (f.sub.r), change the amplitude of a terminal voltage when the frequency component (f.sub.r) is a decreasing frequency.

2. The permanent magnet synchronous machine according to claim 1, further comprising a display device for displaying the frequency component (f.sub.r) that deviates from the feed frequency (f.sub.0).

3. The permanent magnet synchronous machine according to claim 1, wherein the motor controller is further configured to change a frequency of the terminal voltage to a frequency of the rotor (R).

4. The permanent magnet synchronous machine according to claim 1, further comprising a converter configured to supply the feed alternating voltage, and the motor controller is configured to change a converter frequency of the converter and to a frequency of the rotor (R).

5. The permanent magnet synchronous machine according to claim 1, wherein the synchronous machine is a single-phase synchronous machine.

6. A method for operating a permanent magnet synchronous machine according to claim 1 including the steps of: a. applying the feed alternating voltage with the feed frequency (f.sub.0) to the terminals of the synchronous machine; b. monitoring the terminal current on the connection terminals and the current frequency (f.sub.a); and c. determining whether the current frequency (f.sub.a) of the terminal current contains the frequency component (f.sub.r) with a frequency that deviates from the feed frequency (f.sub.0) and whether the frequency component (f.sub.r) is decreasing.

7. The method according to claim 6 further comprising adapting at least one of the frequency and the amplitude of the terminal voltage is carried out as soon as, in c), a detection of the frequency component (f.sub.r) with a frequency that deviates from the feed frequency (f.sub.0) is determined and is decreasing.

8. The method according to claim 7, wherein the adaptation of the at least one of the frequency and the amplitude of the terminal voltage takes place so that the rotor continues to rotate at a constant rotational speed.

Description

DRAWINGS

(1) The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

(2) FIG. 1 is a schematic view of an exemplary embodiment of the disclosure.

(3) FIG. 2 is a schematic view of the exemplary embodiment according to FIG. 1 where the frequency of the terminal voltage has changed.

DETAILED DESCRIPTION

(4) The disclosure is explained in more detail in the following with reference to FIGS. 1 and 2. Use of the same reference numerals indicates the same structural and/or functional features.

(5) FIGS. 1 and 2 each show a permanent magnet synchronous machine 1 with a rotor R and a stator S. The stator S is formed with connection terminals 2. The terminals 2 apply a supply alternating voltage or converter voltage with a frequency f.sub.0. The permanent magnet synchronous machine 1 is equipped with a motor controller 10. It includes an assembly 11 to detect the terminal current i.sub.K(t) on the connection terminals 2 and the current frequency f.sub.a. The motor controller 10 may include a converter.

(6) The analysis device 12 is formed in order to determine whether the current frequency f.sub.a of the terminal current i.sub.K(t) contains a frequency component f.sub.r with a frequency that deviates from the feed frequency f.sub.0 and particularly if it is decreasing.

(7) FIG. 2 further shows (only by example) a voltage curve of the induced voltage (Ur(t), which has a lower frequency f.sub.r than the frequency f.sub.0. This reflects the decreasing rotational speed of the synchronous machine 1 when out of synchronization.

(8) Furthermore, a display device 13 is provided. It displays a frequency component f.sub.r that deviates from the supply frequency (f.sub.0) and/or that it is decreasing. Depending on the determined frequency component f.sub.r, the motor controller 10 adapts the frequency and the amplitude of the terminal voltage to the frequency of the rotor R when the motor is fed not by supply voltage but by the converter.

(9) The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.