A new method to suppress the limit cycle of PWM Inverter

Digitally controlled PWM inverters are interfered by quantization errors caused by A/D converters (ADC) and Digital Pulse-Width Modulators (DPWMs), which may result in undesirable limit-cycle oscillations (LCO). In this paper, static and dynamic models that include the quantization effects are derived and used to explain the origins of LCO. According to a brief analysis of the limit cycle oscillation period and amplitude, a new method to improve digital PWM resolution is introduced in the paper. By this method, the limit cycle can be avoided with the proposed integral part so that it will not propagate to the output directly. Therefore the digital PWM resolution is improved largely. In the end, the conclusions are illustrated by simulation and experimental examples.