Patent ID: 8816612
Filing Date: 2014-08-26
Classification: H02M,H02P

Abstract:
1. A controller for a multi-phase rotary device comprising: an electric power inverter for converting an electric power of a direct current power source by a pulse width modulation control method and for supplying a converted electric power to the multi-phase rotary device, the electric power inverter including a plurality of switching devices, which have a high voltage side switching device and a low voltage side switching device connected to each other in a bridge connection manner; a control calculation device including: a duty command device for calculating a duty command value, which relates to the pulse width modulation control method, with a predetermined calculation period; and a pseudo duty calculation device for calculating a update duty value based on the duty command value with an update period, which has a frequency M times larger than the calculation period, the M indicative of an integer equal to or larger than two, the control calculation device outputting the update duty value corresponding to a command voltage of the multi-phase rotary device; a carrier wave comparison device for comparing the update duty value with a carrier wave of the pulse width modulation control method and for generating an on-off signal of each switching device; and a current detection device for detecting current of each phase to be supplied to the multi-phase rotary device from the electric power inverter with the calculation period, the current detection device arranged between the low voltage side switching device and a negative terminal of the direct current power source or between the high voltage side switching device and a positive terminal of the direct current power source, wherein: the duty command device changes an average voltage of each phase corresponding to the duty command value so that an on-state time of a detection side switching device corresponding to the duty command value is equal to or longer than a minimum detection time for detecting the current of each phase with the current detection device; the detection side switching device is provided by one of the switching devices disposed on a current detection device side; the pseudo duty calculation device calculates the update duty value, which corresponds to a N-th duty command value, based on the N-th duty command value and a (N−1)-th duty command value in accordance with a ratio between the update period and the calculation period with a linear compensation method; the duty command device calculates the duty command value N times; the N indicates a natural number; the pseudo duty calculation device outputs a pseudo duty value when the on-state time of the detection side switching device of at least one of phases, which corresponds to the update duty value, is smaller than the minimum detection time; and the pseudo duty value is prepared by changing the update duty value so as to detect the current of all phases other than the at least one of phases.