Abstract: A method for driving a multiphase motor by a drive circuit, wherein the drive circuit comprises a plurality of transistors, and for each phase of the motor are provided a first path and a second path, wherein at least one transistor is assigned to the first path and to the second path of each of the different phases, and wherein a normal mode, a first drive mode, and a third drive mode are provided, wherein for the first drive mode, all the transistors in the second paths are short-circuited, and for the third drive mode, all the transistors are opened. The method includes detecting an undervoltage or an overvoltage in the drive circuit, operating the drive circuit in the first drive mode if a first undervoltage has been detected, and operating the drive circuit in the second drive mode if a second undervoltage has been detected.

Abstract: A method for operating an electronically commutated synchronous machine with several phases, wherein an actuation circuit operates the synchronous machine, the actuation circuit having at least two switches for each phase and a degree of actuation for each phase being periodically ascertained by the actuation circuit, wherein the switch-on period, during which a supply voltage is applied to the respective phase by way of the associated switch, is determined for ascertaining the degree of actuation, wherein the following steps are carried out: measuring current by a single measurement resistor in at least two measurement windows and shifting one or more of the switch-on periods of the different phases relative to one another as soon as the difference between switch-on instants of at least two phases falls below a minimum period or the difference between the switch-on periods of at least two phases falls below twice the minimum period.

Abstract: A method for operating an electronically commutated synchronous machine with several phases, wherein an actuation circuit operates the synchronous machine, the actuation circuit having at least two switches for each phase and a degree of actuation for each phase being periodically ascertained by the actuation circuit, wherein the switch-on period, during which a supply voltage is applied to the respective phase by way of the associated switch, is determined for ascertaining the degree of actuation, wherein the following steps are carried out: measuring current by a single measurement resistor in at least two measurement windows and shifting one or more of the switch-on periods of the different phases relative to one another as soon as the difference between switch-on instants of at least two phases falls below a minimum period or the difference between the switch-on periods of at least two phases falls below twice the minimum period.

Abstract: A method for driving a multiphase motor by a drive circuit, wherein the drive circuit comprises a plurality of transistors, and for each phase of the motor are provided a first path and a second path, wherein at least one transistor is assigned to the first path and to the second path of each of the different phases, and wherein a normal mode, a first drive mode, and a third drive mode are provided, wherein for the first drive mode, all the transistors in the second paths are short-circuited, and for the third drive mode, all the transistors are opened. The method includes detecting an undervoltage or an overvoltage in the drive circuit, operating the drive circuit in the first drive mode if a first undervoltage has been detected, and operating the drive circuit in the second drive mode if a second undervoltage has been detected.