Method for reducing a number of switching cycles when controlling a multiphase converter

Patent metadata

Field	Value
Publication number	US-9571007-B2
Application number	US-201214362432-A
Country	US
Kind code	B2
Filing date	Nov 29, 2012
Priority date	Dec 3, 2011
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

A method for controlling a polyphase inverter that includes a number of half bridges connected into an intermediate voltage circuit and center taps between switching elements. By cyclically switching the switching elements, the respective center taps of the half bridges are connected to an upper intermediate circuit rail or to a lower intermediate circuit rail of the intermediate voltage circuit according to the principle of pulse width modulation. The switching elements of at least one half bridge are driven in a modified manner, at least in some time intervals, in that the switching pulses of at least two consecutive periods of the pulse width modulation are concatenated directly in time as one switching pulse. In this way, the switching frequencies of the correspondingly driven switching elements and thus the switching losses of the latter can be further reduced.

First claim

The invention claimed is:

1. A method of controlling a polyphase inverter, the polyphase inverter having a plurality of half bridges switched into a DC link with an upper busbar and a lower busbar, having switching elements, and center taps between the switching elements, the method comprising:
by clocked switching of the switching elements with pulse width modulation, connecting respective center taps of the half bridges to the upper busbar or to the lower busbar of the DC link; and
driving the switching elements of at least one half-bridge in modified form at least during given time segments by temporally arranging the switching pulses of at least two successive periods of the pulse width modulation directly next to one another as one switching pulse;
wherein a number of switching cycles is reduced when performing the step of driving the switching elements of the at least one half-bridge in the modified form in comparison to a situation where the switching elements of the at least one half-bridge is not driven in the modified form.

2. The method according to claim 1 , which comprises driving the switching elements of at least one half bridge in modified form by arranging the switching pulses of at least three successive periods temporally directly next to one another as one switching pulse.

3. The method according to claim 1 , which comprises driving the switching elements of different half bridges in modified form at different times.

4. The method according to claim 1 , which comprises, at least in time segments, simultaneously driving the switching elements of a plurality of half bridges in modified form.

5. The method according to claim 1 , which comprises performing the step of driving the switching elements of the at least one half-bridge in the modified form at least during the given time segments depending on a parameter characterizing an AC user connected to the inverter.

6. The method according to claim 1 , which comprises controlling a three phase inverter.

7. The method according to claim 1 , which comprises effecting the modified control and the regular control in temporal alternation.

8. The method according to claim 1 , which comprises increasing a clock frequency of the pulse width modulation at least during the time segments of the modified control.

9. The method according to claim 4 , which comprises driving the switching elements of the respectively other half bridges by shortening a time interval of the switching pulses corresponding to an original time interval of the switching pulses arranged next to one another in periods of a modified control.

10. The method according to claim 5 , wherein the parameter is a parameter characterizing a load state and/or an operating state of the AC user.

11. The method according to claim 6 , which comprises operating the three phase inverter using a modulation method selected from the group consisting of three phase clocking, two phase clocking, and single phase clocking, and thereby driving, at least in time segments, the switching elements of at least one of the respectively clocked half bridges in modified form.

12. The method according to claim 1 , which comprises, at least in time segments, driving in modified form the switching elements of a given half-bridge whose center tap is presently being switched with a greatest duty factor.

13. The method according to claim 11 , which comprises operating the three phase inverter using a modulation method of three phase clocking or two phase clocking, and thereby driving, at least in time segments, the switching elements of two clocked half bridges in modified form.

14. The method according to claim 12 , which comprises driving the switching elements of the respectively other half bridges by shortening a time interval of the switching pulses corresponding to an original time interval of the switching pulses arranged next to one another in periods of a modified control.

Assignees

• Diehl Ako Stiftung Gmbh & Co

Inventors

• Olarescu Nicola-Valeriu

Classifications

• H02M7/00

  Conversion of AC power input into DC power output; Conversion of DC power input into AC power output · CPC title

• H02P21/06

  Rotor flux based control involving the use of rotor position or rotor speed sensors · CPC title

• H02M7/537

  using semiconductor devices only, e.g. single switched pulse inverters · CPC title

• H02M7/5395 Primary

  by pulse-width modulation · CPC title

• H02M7/53871

  with automatic control of output voltage or current · CPC title