Linear Pulsewidth Modulation Under Fluctuating Power Supply

Heavy fluctuations in the dc power supply cause large distortions, when the simple pulsewidth modulation technique is employed in inverters. The ripples in the dc supply may even be synchronous with the converted ac signal. To overcome this nonlinear distortion, a new carrier signal is generated by multiplying the triangular dither signal with the dc supply voltage, without changing the basic dither frequency. The modulator–demodulator characteristic becomes linear, thereby removing the distortion.