Patent ID: 8638052

Claim:
A method of controlling an electric synchronous machine having a stator and a moving part, said method comprising the following steps: operating the machine with a deceleration moment (M p ) so that a speed of the moving part of the machine is reducing, monitoring the movement of the moving part of the machine, transitioning to a holding mode upon detection of a direction reversal or a speed (v) of the moving part of approximately zero by impressing at least one current pattern (I; i u , i v , i w ) of string currents in the stator of the machine, wherein, in the holding mode, a phase position of the current pattern (I; i u , i v , i w ) with respect to a coordinate system of the stator system is held substantially constant, and wherein the current pattern forms a current vector (I) in space vector representation of a moving part coordinate system (D, Q), the amplitude of which is proportional to a currently demanded deceleration braking moment (M B ), and which at the beginning of the holding mode is impressed such that a phase position of the current vector (I) of approximately −90° electrical in relation to the direction of movement of the space vector of the induced moving part voltage (U EMK ) is obtained after standstill, and thus an effective braking moment (M B ) of the machine becomes approximately zero, and maintaining the current pattern (I; i u , i v , i w ) until, with movement of the moving part and influence of an external moment (M A ) acting on the machine, a stable equilibrium of moments between the external moment (M A ) and the braking moment (M B ) of the machine is established.