Patent ID: 9356549
Filing Date: 2016-05-31
CPC Classification: H02P

Claim Text:
1. A control device of a three-phase alternate current motor comprising: an inverter having a plurality of switching elements for driving the three-phase alternate current motor; at least one current sensor, which senses a current flowing in a respective phase among three phases of the alternate current motor at a given sampling timing; and a control means that switches on and off each switching element of the inverter by feeding back a plurality of dq axis current calculated values, which are obtained by dq transforming a plurality of phase current sensed values in two or more phases sensed by a plurality of current sensors, or obtained by dq transforming a phase current sensed value of one phase and a current estimated value of other phase estimated from the phase current sensed value of the one phase, to a plurality of dq axis current command values, or by feeding back a torque estimated value, which is estimated based on the dq axis current calculated values, to a torque command value, so that the control means controls the current passing through the three-phase alternate current motor, wherein the control means includes at least one first order current operation part that: expands a phase current sensed value of one phase in Fourier series as a function of an electric angle; extracts a first order component of the Fourier series; and operates a first order current operated value of the one phase, wherein the at least one first order current operation part integrates a calculated value based on the phase current sensed value of the one phase at an integral angle for k periods of the electric angle so that Fourier coefficients are calculated, wherein the integral angle is set by dividing the k periods of the electric angle by N, and wherein k represents a natural number, and N represents another natural number, wherein the at least one first order current operation part calculates the first order current operated value of the one phase based on the Fourier coefficients, wherein the control means dq transforms the first order current operated value to calculate the dq axis current calculated value, wherein the control means feeds back the dq axis current calculated value to the dq axis current command value, or the torque estimated value, which is estimated based on the dq axis current calculated value, to the torque command value.