POLE-POSITION DETECTOR OF SYNCHRONOUS MOTOR

摘要

The invention relates to a magnetic-pole position detecting apparatus for a synchronous motor. An arithmetic section (2) outputs six kinds of voltage vectors having equal amplitudes and equal-interval phases to a circuit section (3) as a voltage vector command (V) . The circuit section (3) makes the voltage vectors to be applied to a synchronous motor (1), outputs a trigger signal (Tr) to a detection section (4) each time after finishing the application of each voltage vector, and makes a detection current (Di) of each phase to be detected. Thereafter, the arithmetic section (2) calculates and outputs magnetic-pole positions (θ) at every 60/ (2^k) degrees (where k is a natural number) based on the detection current (Di). Each voltage vector is applied for a time period sufficient enough for each phase winding to be magnetically saturated in the order that the phases of each voltage vector either increase monotonously or decrease monotonously. In detecting the magnetic-pole positions, the arithmetic section (2) generates an added current value that is a result of an addition of current values for each combination of every 180-degree different phases from among current values that are in phase with the voltage vectors. The arithmetic section (2) specifies magnetic-pole positions (θ) based on the added current values.