| 摘要 |
A method for determining a time for a zero crossing of a phase current in a polyphase electrical machine (2). The method including driving a driver circuit (31; 50) for providing phase voltages to operate the electrical machine (2); deactivating a pulse-width-modulated driving by at least one power switch (36, 37; 52, 53), such that no potential is applied to connecting nodes (AI, A2, B1, B2) by the driver circuit (31; 50), 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 (36, 37; 52, 53) 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 (40; 54) within the time segment. |
