Chapter 9
Application of Chaotic Modulation
With the advent of pulse width modulation (PWM), switching power converters have received a great attraction for application in electric drive systems, because of the advantages of flexible power control, compact size, and high efficiency. In general, the PWM DC–DC converter (usually called the DC chopper) functions to control the applied voltage or current for DC drive systems, whereas the PWM DC–AC converter (usually called the AC inverter) is to simultaneously control the applied voltage or current and frequency for AC drive systems. However, because of the nature of switching, those advantages are counterbalanced by the generation of harmonics, electromagnetic interference (EMI), and acoustic noise. Increasingly, there is a trend for pushing up the switching frequency of modern electric drive systems, hence reducing their volume and weight. This trend inevitably contributes to an increasing level of EMI. It also degrades the electromagnetic compatibility (EMC) of electronic devices.
Conventionally, the aforementioned EMI problems are alleviated by filtering the output or shielding the setup. In recent years, attention has been focused on using signal processing rather than filtering or shielding – namely, developing various PWM schemes for inverter-fed AC drive systems.
In this chapter, chaos is applied to PWM schemes for inverter-fed AC drive systems, hence reducing the corresponding audible noise and mechanical vibration. The open-loop ...
