| 摘要 |
<P>PROBLEM TO BE SOLVED: To execute stable control of three-phase AC power by surely detecting a current of each phase by a simple configuration. <P>SOLUTION: A power conversion device drives and controls a three-phase motor. The power conversion device is equipped with: an inverse parallel circuit composed of a switching element and a diode, each current detecting resistor of each lower arm of each phase; a gain adjustment part for amplifying a voltage signal of each current detecting resistor; a sample hold circuit for sampling each voltage signal amplified by the gain adjustment part; a CPU that captures each sampled voltage signal as a current signal of each phase, generates a PWM signal on the basis of each current signal, and also, generates a sampling signal of the sample hold circuit; and a gate drive circuit. When switching elements of the lower arms of two or more phases in the same carrier period of the PWM signal are turned ON, the CPU generates the sampling signal in synchronization with the PWM signal to the switching element of the lower arm having the shortest ON-time. <P>COPYRIGHT: (C)2011,JPO&INPIT |
