POLE-POSITION DETECTOR OF SYNCHRONOUS MOTOR

摘要

A magnetic-pole position detecting apparatus for a synchronous motor includes an arithmetic section outputting six voltage vectors having equal amplitudes and equal-interval phases to a circuit section as a voltage vector command. The circuit section applies the voltage vectors to a synchronous motor, outputs a trigger signal to a detection section each time after finishing the application of each voltage vector, and detects each phase. Thereafter, the arithmetic section calculates and outputs magnetic-pole positions at every 60/(2k) degrees (where k is a natural number based on the detection current. Each voltage vector is applied for a time period sufficient for each phase winding to be magnetically saturated in an order so that the phases of each voltage vector either increase monotonically or decrease monotonically. Tn detecting the magnetic-pole positions, the arithmetic section generates an added current value that is a result of an adition 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 specifies magnetic-pole positions based on the added current values.