Electric motor comprising a device for generating a sequence of signals

Patent metadata

Field	Value
Publication number	US-9876457-B2
Application number	US-201415101501-A
Country	US
Kind code	B2
Filing date	Dec 2, 2014
Priority date	Dec 4, 2013
Publication date	Jan 23, 2018
Grant date	Jan 23, 2018

Abstract

The invention relates to an electric motor ( 1 ), in particular a fan motor, comprising a device ( 5 ) for generating a sequence ( 3 ) of signals that comprises a plurality of especially blocks ( 22 ) of signals. The blocks ( 22 ) of signals comprise a plurality of signals ( 19 ) having a specific signal duration ( 20 ). According to the invention, the signal duration ( 20 ) of the individual signals ( 19 ) varies.

First claim

The invention claimed is:

1. An electric motor ( 1 ) comprising a device ( 5 ) for generating a sequence ( 3 ) of signals, said sequence ( 3 ) of signals comprising a plurality of signal blocks ( 22 ) and said signal blocks ( 22 ) comprising a plurality of signals ( 19 ) having a specific signal duration ( 20 ), characterized in that the signal duration ( 20 ) of the individual signals ( 19 ) varies; wherein the signal duration ( 20 ) of the signals ( 19 ) of the second signal group are calculated such that the defined duration of a signal block ( 23 ) and the sum of the signal duration ( 20 ) of all the signals ( 19 ) of a signal block ( 22 ) are substantially the same.

2. The electric motor ( 1 ) according to claim 1 , characterized in that a signal block ( 22 ) comprises a defined number n of signals ( 19 ) and the duration at least of two signal blocks ( 22 ) is constant.

3. The electric motor ( 1 ) according to claim 1 , characterized in that the electric motor ( 1 ) is actuated by the sequence ( 3 ) of signals.

4. The electric motor ( 1 ) according to claim 1 , characterized in that each signal block ( 22 ) comprises a first and a second signal group, wherein the signals ( 19 ) of the first signal group are emitted before the signals ( 19 ) of the second signal group and the signal duration ( 20 ) of the n−2 signals of a signal block of the first signal group is determined by a random generator ( 52 ).

5. The electric motor ( 1 ) according to claim 1 , characterized in that the signal duration ( 20 ) of the signals ( 19 ) of the second signal group are calculated or extracted from a second table.

6. The electric motor ( 1 )) according to claim 1 , characterized in that the sequence ( 3 ) of signals is a pulse-width modulated sequence ( 3 ) of signals and the signal duration ( 20 ) of a signal ( 19 ) comprises at least the duration of a pulse ( 11 ) and at least the duration of a pulse pause.

7. The electric motor ( 1 ) according to claim 1 , characterized in that a first and a second limit value define a range for the variation of the signal duration ( 20 ) of the signals ( 19 ).

8. The electric motor ( 1 ) according to claim 1 , where the electric motor ( 1 ) is a fan motor.

9. The electric motor ( 1 ) according to claim 2 , wherein the duration of all the signal blocks ( 22 ) is constant.

10. The electric motor ( 1 ) according to claim 3 , characterized in that the electric motor ( 1 ) is actuated directly by the sequence ( 3 ) of signals.

11. The electric motor ( 1 ) according to claim 3 , characterized in that the electric motor ( 1 ) is actuated via a motor control unit ( 56 ) by the sequence ( 3 ) of signals.

12. The electric motor ( 1 ) according to claim 1 , characterized in that each signal block ( 22 ) comprises a first and a second signal group, wherein the signals ( 19 ) of the first signal group are emitted before the signals ( 19 ) of the second signal group and the signal duration ( 20 ) of the n−2 signals of a signal block of the first signal group is determined by a table ( 54 ).

13. The electric motor ( 1 ) according to claim 12 wherein the table ( 54 ) is a look-up table.

14. The electric motor ( 1 ) according to claim 1 , characterized in that the signal duration ( 20 ) the two last signals ( 19 ) of a signal block of the second signal group are calculated or extracted from a second table.

Assignees

• Bosch Gmbh Robert

Inventors

• Becker Markus
• Vollmer Ulrich

Classifications

• F04D25/08

  the working fluid being air, e.g. for ventilation · CPC title

• H02P27/085 Primary

  wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency · CPC title

• H02P29/50 Primary

  Reduction of harmonics · CPC title

• H02P2209/09

  PWM with fixed limited number of pulses per period · CPC title