21-03-2013 дата публикации
Номер: US20130069574A1
A method for determining a time for a zero crossing of a phase current in a polyphase electrical machine (). The method including driving a driver circuit () for providing phase voltages to operate the electrical machine (); deactivating a pulse-width-modulated driving by at least one power switch (), such that no potential is applied to connecting nodes (AI, A, B, B) by the driver circuit (), at least during a time segment in each cycle of the pulse width modulation; detecting a diode voltage via a freewheeling diode, with which the deactivated power switch () has been provided, within the time segment; and fixing the time for the zero crossing of the phase current as the time after which there is no longer a diode voltage present across the freewheeling diode () within the time segment. 12231503637525312122363752531212. A method for determining a time of a zero crossing of a winding phase current in a polyphase electric machine () , the electric machine () being actuated with the aid of a driver circuit (; ) with power switches (; ; , ) in order to provide a plurality of phase voltages , which are applied to connection nodes (A , A , B , B) of the electric machine () which are associated with corresponding phases , at least some of the power switches ( , ; , ) being actuable cyclically on the basis of pulse width modulation with a duty factor in order to apply different potentials alternately to one of the connection nodes (A , A , B , B) , said method comprising the following steps:{'b': 31', '50', '2, 'actuating the driver circuit (; ) for providing the phase voltages in order to operate the electric machine ();'}{'b': 36', '37', '52', '53', '31', '50', '1', '2', '1', '2, 'deactivating the pulse-width-modulated actuation for at least one of the power switches (, ; , ), such that, at least during a time segment in each cycle of the pulse width modulation, no potential is applied by the driver circuit (; ) to the connection nodes (A, A, B, B);'}{'b': 36', '37', ' ...
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