PWM strategies for the real-time embedded control and condition monitoring of AC drives

The authors´ control of AC drives can be efficiently achieved by the use of inverters utilising modern power electronic devices. With the advancement of microcontroller technology, it has become possible to control AC drives with complex PWM waveforms generated by using calculating algorithms while the system is online. Such algorithms allow the manipulation of various parameters within the modulation strategy which can result in changes in the output frequency content. The authors investigate this property to provide clear regions in the spectrum of a PWM waveform in order to allow unhindered examination for signature components used in online fault diagnostic methods. A hardware board using the Intel 8097 microcontrollers in multiprocessor communication mode with master-slave configuration has been designed. The software modules are designed with an emphasis on standardisation of interface to the hardware.