Magnetic-pole position detection apparatus for synchronous machines

摘要

An object is to provide a magnetic-pole position detection apparatus for synchronous machines that allows a desired accuracy of magnetic-pole position detection regardless of variation in DC voltage of a DC voltage source. Calculation means (2a) changes a pulse width (tp) and a pulse-quiescent width (tn) in accordance with a DC voltage detection value (Vdc), using a pulse width determination section (22a), such that a desired accuracy of magnetic-pole position detection can be obtained regardless of variation in DC voltage of a DC voltage source (5). The calculation means (2a) also performs control such that a sampling timing is fixed at the end point of the pulse width (tp) of voltage vectors regardless of the DC voltage detection value (Vdc).

主权项

1. A magnetic-pole position detection apparatus for synchronous machines, comprising:
circuit means for converting a DC voltage of a DC voltage source to voltage vectors based on a voltage vector instruction, and applying the voltage vectors to a synchronous machine having windings for n phases (n is a natural number larger than or equal to three); current detection means for detecting an electric current flowing in each of the windings of the synchronous machine; and calculation means for calculating and outputting 2n voltage vectors to the circuit means as the voltage vector instruction, and for acquiring a current detection value from the current detection means at a predetermined sampling timing based on the voltage vector instruction, the 2n voltage vectors being determined depending on the DC voltage of the DC voltage source, having equal amplitudes, having phases shifted by equal amounts in one cycle (360 degrees), and having equal predetermined pulse widths, wherein when the voltage vectors based on the voltage vector instruction are applied to the synchronous machine, the calculation means further calculates n added current values by adding up current detection values acquired at the sampling timing as a result of application of each pair of voltage vectors whose phases are different from each other by 180 degrees, and detects a magnetic-pole position during stoppage of the synchronous machine, based on the n added current values, the magnetic-pole position detection apparatus comprising DC voltage detection means for detecting the DC voltage of the DC voltage source, wherein the calculation means controls the pulse width and the sampling timing, based on a DC voltage detection value from the DC voltage detection means, so as to obtain a desired accuracy of magnetic-pole position detection regardless of variation in the DC voltage of the DC voltage source.