Patent ID: 11926377
Assignee: THYSSENKRUPP PRESTA AG
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC B  H | IPC B  H

Claim 11:
12. A control unit for driving a multiphase electric motor of an electromechanical motor vehicle power steering system that includes a motor controller, a driver circuit connected to the motor controller, high-side and low-side switching elements driven by the driver circuit, at least three connection lines to which phase windings of the multiphase electric motor are connectable, wherein the at least three connection lines each have a phase disconnection device that is configured to be driven the driver circuit and by way of the driver circuit are each alternately connectable via one of the high-side and low-side switching elements to a respective pole of a DC voltage source, and a current measuring device for measuring a current flowing between the poles of the DC voltage source, wherein the control unit performs the method comprising:
monitoring the low-side and high-side switching elements for short-circuit faults during operation of the multiphase electric motor;
switching off the low-side and high-side switching elements upon detection of a short-circuit fault;
determining whether one of the first high-side switching elements or one of the low-side switching elements is causing the short-circuit fault;
to brake the multiphase electric motor, switching on a second of the high-side switching elements or correspondingly a second of the low-side switching element in addition to the one of the first high-side switching elements or the one of the low-side switching elements causing the short-circuit fault;
switching off the low-side and high-side switching elements after a selectable braking period has elapsed; and
opening the respective phase disconnection devices.