Method for Controlling a Brake System

摘要

A brake system comprises a cylinder-piston unit movable by an electromechanical actuator. Wheel brakes associated with at least one axle can be supplied with braking pressure via the hydraulic pressure chamber. The electromechanical actuator comprises a rotation-translation transmission and an electronically commutated synchronous machine having a stator with at least two phase windings, a rotor comprising at least one permanent magnet and at least one rotor position sensor. A torque-forming current and/or a magnetic field attenuating current are adjusted in a co-ordinate system which is fixed relative to the rotor. Voltages in the co-ordinate system are detected to serve as control variables and are transformed into a voltage phasor, which indicates for each phase winding of the stator, a voltage to be applied, and a set value for the magnetic field attenuating current is limited to a maximum value being determined from a predetermined characteristic map.

主权项

1. A method of operating a brake system for motor vehicles with an electrically controllable pressure supply device comprising:
supplying brake pressure to a plurality of hydraulic wheel brakes from a hydraulic pressure chamber; displacing a piston within the hydraulic pressure chamber with an electromechanical actuator, wherein the electromechanical actuator comprises a rotation-translation gearbox and an electrical machine, wherein the electrical machine is an electronically commutated synchronous machine having a stator with at least two phase windings and a rotor comprising at least one permanent magnet as well as at least one rotor position sensor; regulating at least one of a torque-forming current and a magnetic field attenuation current in a coordinate system that is fixed relative to the rotor; transforming voltages in the coordinate system into control variables using the measured rotor position, wherein the control variable are a voltage vector that gives a voltage to be applied for each phase winding of the stator; and determining a measured revolution rate of the rotor from a predetermined characteristic field; and limiting a target value for the magnetic field attenuation current to a maximum value according to the measured revolution rate.