Ascertaining actual value of internal voltage of async. machine - deriving ohmic or inductive voltage drop in each winding from measured external machine voltage

摘要

The external machine voltage is measured. The ohmic or inductive voltage drop in the separate windings is ascertained on the basis of the current flow and speed of current charge in the individual windings of the async. machine. The drop is derived from the external voltage. The total machine voltage (UM) including the current-dependent voltage drops at a resistance (RV) and inductance (Ldelta) can be tapped at the motor terminals. The voltage at the main unductance (Vi) represents the actual regulating value. For an n-phase async. machine the voltage drop is tapped phase-correct for each 360 deg./(2xn) motor voltage sector. USE - Tacho-less regulation of current in async. machine.