Patent ID: 8866430
Filing Date: 2014-10-21
Classification: H02M,H02P,Y02B

Abstract:
1. An apparatus for controlling a boost converter in a motor drive system, said drive system comprising: a direct current power supply; a three-phase alternating current motor; an electric power converter disposed between the direct current power supply and the three-phase alternating current motor, the electric power converter including switching circuits, each of which corresponds to respective one of three phases of the three-phase alternating current motor, and a smoothing condenser, which is disposed electrically in parallel with the switching circuits; and the boost converter disposed between the electric power converter and the direct current power supply, the boost converter boosting a direct current voltage of the direct current power supply and supplying it to the electric power converter, said apparatus for controlling the boost converter comprising: an operating device comprising a proportional element, an integral element and a derivative element, the derivative element being configured as a bandpass filter, said operating device calculating a PID controlled variable corresponding to an electric current command value of the boost converter for maintaining an output voltage of the boost converter at a command value of an inter-terminal voltage VH of the smoothing condenser; a controlling device for controlling the output voltage of the boost converter on the basis of the calculated PID controlled variable; a judging device for judging whether or not suppress of loss associated with input/output of an electric power on the direct current power supply is to be prioritized over suppression of variation in the inter-terminal voltage VH; and a switching device for switching an operation mode when said operating device calculates the PID controlled value from a variation suppression mode in which a cutoff frequency of the bandpass filter is maintained at a reference value to a loss suppression mode in which the cutoff frequency is corrected to a reduction side with respect to the reference value if it is judged that the loss suppression is to be prioritized, in the loss suppression mode, the cutoff frequency being corrected to a lower frequency side at a lower rotational speed of the three-phase alternating current motor.