The invention is directed to a powder supply system (1) for use in an apparatus (100) for producing a three-dimensional work piece by irradiating layers of a raw material powder (4) with electromagnetic or particle radiation. The powder supply system (1) comprises a circuit line (7) configured to conduct a gas stream (9), a conveying device (19) configured to convey the gas stream (9) through the circuit line (7), a powder doser (8) configured to introduce a desired dose of raw material powder (4) into the gas stream (9) flowing through the circuit line (7), a measuring unit (15) configured to measure at least one of a pressure and a volume flow in the circuit line (7) at a position downstream of the powder doser (8), and a control unit (40) configured to control the powder doser (8) based on at least one of a pressure value and a volume flow value measured by the measuring unit (15) in such a manner that the at least one of the pressure value and the volume flow value measured by the measuring unit (15) is within a predetermined range.