| 摘要 |
PURPOSE:To realize a pulse width modulation in which the basic frequency component of output voltage from a PWM inverter matches a voltage command value constantly from multipulse mode to small pulse mode. CONSTITUTION:When an AC voltage command value is defined by ¦V¦xsintheta, an AC voltage command output circuit 11 outputs the amplitude ¦V¦ and the voltage command phase theta. A comparison wave output means 31 outputs comparison waves Vc1, Vc2 based on the voltage command phase theta and a pulse mode command delivered from a pulse mode command output circuit 12. The comparison waves Vc1, Vc2 have been previously operated according to Fourier transform while taking account of basic frequency components and stored. A positive/ negative switching means 32 outputs a signal Vs having amplitude ¦V¦ with the sign thereof being switched depending on the phase theta. A comparing means 33 compares the comparison waves Vc1, Vc2 and produces a PWM control signal. |
