PARAMETERIZATION METHOD FOR A CONVERTER AND CONVERTER IMPLEMENTING THE METHOD

Abstract

The present invention relates to a parameterization method for a converter (1, 2) of the speed controller type, the said converter (1, 2) being connected to an electrical load (3) by means of an electrical cable (4) comprising at least two conductors, the method consisting in: generating common-mode current on the electrical cable (4) starting from a pulsed voltage comprising a first voltage edge (11, 13) and a second voltage edge (12, 14) delayed by a delay time (T) with respect to the first voltage edge (11, 13),measuring the common-mode current generated,making the delay time (T) between the two voltage edges (11, 12, 13, 14) generated vary, and determining an optimal delay time (T2) starting from a quantity (Ipeak, Ieff) representative of the common-mode current measured for the various values of the delay time (T).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages will become apparent in the detailed description that follows referring to one embodiment given by way of example and depicted by the appended drawings in which:

FIG. 1 shows a plot of the voltage signal produced by a two-level converter and the voltage oscillations generated by this voltage signal on the electrical cable.

FIG. 2 shows a circuit diagram of an installation comprising a two-level converter.

FIG. 3 shows a circuit diagram of an installation comprising a three-level converter of the NPC type.

FIG. 4 shows simplified diagrams of the installations in FIGS. 2 and 3.

FIGS. 5A, 5B, 5C are plots showing the curves of the voltage signal produced on the electrical cable by a converter with three or more levels, seen from the converter side, and the voltage oscillations generated by this voltage signal on the electrical cable seen from the load side.

FIGS. 7A to 7E are plots each showing the common-mode current signal measured at the output of the converter on one conductor of the electrical cable as a function of the voltage signal applied to this conductor which are respectively illustrated by the curves in FIGS. 6A to 6E.

FIGS. 8A and 8B show plots on each of which is shown the voltage signal transmitted over one individual conductor of the cable by means of a converter with two or more levels.

FIG. 9 shows a simplified curve profile representing the variation of the peak intensity of the common-mode current as a function of the delay time observed between the transmission of the two voltage edges.

FIG. 10 shows a simplified curve profile representing the variation of the r.m.s. intensity of the common-mode current as a function of the delay time observed between the transmission of the two voltage edges.

FIG. 11 shows the signal of the voltage obtained after the transmission of a voltage edge towards the load and a reflection of this voltage edge on the converter set in a high-impedance state.

FIG. 12 shows the intensity signal obtained for certain types of cables, after the transmission of a voltage edge towards the load and a reflection of this voltage edge on the converter set in a high-impedance state.

Claims

1. A parameterization method for a converter (1, 2) of the speed controller type, the said converter (1, 2) being connected to an electrical load (3) by means of an electrical cable (4) comprising at least two conductors, the method being characterized in that it consists in: generating common-mode current on the electrical cable (4) starting from a pulsed voltage delivered by the converter (1, 2) to the electrical load (3), the pulsed voltage comprising a first voltage edge (11, 13) and a second voltage edge (12, 14) delayed by a delay time (T) with respect to the first voltage edge (11, 13),measuring the common-mode current generated,making the delay time (T) between the two voltage edges (11, 12, 13, 14) generated vary, determining and storing an optimal delay time (T2) starting from a quantity (Ipeak, Ieff) representative of the common-mode current measured for the various values of the delay time (T).

2. Method according to claim 1, characterized in that the first voltage edge (11) is generated on one conductor of the cable (4) between an initial value (V0) and an intermediate value (VM) and in that the second voltage edge (12) is generated on the same conductor of the cable (4), in the same pulse direction and offset by the delay time (T), between the intermediate value (VM) and a final value (VC).

3. Method according to claim 1, characterized in that the first voltage edge (13) is generated on a first conductor of the cable (4) between an initial value (V0) and a final value (VC) and in that the second voltage edge (14) is generated on a second conductor of the cable (4), in the same pulse direction and offset by the delay time (T), between the initial value (V0) and the final value (VC).

4. Method according to one of claims 1 to 3, characterized in that the quantity representative of the common-mode current is the peak intensity (Ipeak) of the common-mode current.

5. Method according to claim 4, characterized in that the optimal delay time (T2) is determined by detecting the slope break point of the peak intensities (Ipeak) determined when the delay time (T) increases.

6. Method according to one of claims 1 to 3, characterized in that the quantity representative of the common-mode current is the r.m.s. intensity (Ieff) of the common-mode current.

7. Method according to claim 6, characterized in that the optimal delay time (T2) is determined by detecting the minimum of the r.m.s. intensities (Ieff) determined for each value of delay time (T) observed.

8. Method according to one of claims 1 to 7, characterized in that it consists in determining the propagation time (Tp) of the cable (4) from the optimal delay time (T2) obtained.

9. Method according to one of claims 1 to 8, characterized in that it consists in determining the length of the cable (4) from the optimal delay time (T2) obtained.

10. Converter (1, 2) of the speed controller type which can be connected to an electrical load (3) by means of an electrical cable (4) comprising at least two conductors, the said converter being characterized in that it comprises: means for generating common-mode current starting from a pulsed voltage delivered to the said electrical load (3), the said pulsed voltage comprising a first voltage edge (11, 13) and a second voltage edge (12, 14) delayed by a delay time (T) with respect to the first voltage edge (11, 13),means for measuring the common-mode current (70, 71) generated,means for making the delay time (T) between the two voltage edges (11, 12, 13, 14) generated vary, and means for determining (7) and for storing an optimal delay time (T2) starting from a quantity (Ipeak, Ieff) representative of the common-mode current measured for the various values of delay time (T).

11. Converter according to claim 10, characterized in that it has three or more levels and in that the first voltage edge (11) is generated on one conductor (4a) of the cable (4) between an initial value (V0) and an intermediate value (VM) and in that the second voltage edge (12) is generated on the same conductor (4a) of the cable (4), in the same pulse direction and offset by the delay time (T), between the intermediate value (VM) and a final value (VC).

12. Converter according to claim 11, characterized in that the measurement means comprise a current sensor (70) placed on the conductor (4a) of the electrical cable (4).

13. Converter according to claim 10, characterized in that it has two or more levels and in that the first voltage edge (13) is generated on one conductor (4a) of the cable (4) between an initial value (V0) and a final value (VC) and in that the second voltage edge (14) is generated on a second conductor (4a) of the cable (4), in the same pulse direction and offset by the delay time (T), between the initial value (V0) and the final value (VC).

14. Converter according to claim 13, characterized in that the measurement means comprise a current sensor (70) placed on one of the two conductors (4a, 4b) of the cable (4).

15. Converter according to claim 13, characterized in that the measurement means comprise a current sensor (70, 71) placed on each of the two conductors (4a, 4b) of the cable (4) and in that a summer is capable of adding together the common-mode currents measured on each of the conductors (4a, 4b).

16. Converter according to one of claims 10 to 15, characterized in that the determination means (7) comprise a detector of the peak intensity (Ipeak) of the common-mode current measured for each delay time value (T).

17. Converter according to claim 16, characterized in that the optimal delay time (T2) is the delay time (T) corresponding to the slope break point of the peak intensities (Ipeak) detected when the delay time (T) increases.

18. Converter according to one of claims 10 to 15, characterized in that the determination means (7) comprise a detector of the r.m.s. intensity (Ieff) of the common-mode current measured for each delay time value (T).

19. Converter according to claim 18, characterized in that the optimal delay time (T2) is the delay time (T) corresponding to the minimum of the r.m.s. intensities (Ieff) determined for each delay time value.

20. Converter according to one of claims 10 to 19, characterized in that it comprises means (7) for determining the propagation time (Tp) of the cable (4) from the optimal delay time (T2) obtained.

21. Converter according to one of claims 10 to 20, characterized in that it comprises means (7) for determining the length of the cable (4) from the optimal delay time (T2) obtained.