Spectral characteristics of scanning converters with pulse-width and pulse-frequency-width modulations (PFWMs)
Construction principles and waveform diagrams of scanning converters (SCs) with pulse-width and pulse-frequency-width modulations (PFWMs) that are used in analog and digital control systems for valve converters are considered. Spectral characteristics of SCs of various classes in a wide frequency range of the harmonic interference signal are comparatively analyzed based on mathematical simulation in the Matlab+Simulink environment. The high interference immunity of integrating SCs with PFWMs is proved.
This paper develops a sliding mode-based observer for load torque and parameters variations control of permanent magnet synchronous motor (PMSM) drives. A sliding mode control scheme combined with an observer is useful as a means to depress chattering and the robustness is increased. It is demonstrated that the robustness of an PMSM is improved by using the proposed observer and that the robustness is more enhanced by varying the controller parameters according to the value of the estimate of the disturbance. This paper also presents a detailed comparison of SMC controller with observer for PMSM. The observer designs the implementation aspects, and a comparative study on the extensive experimental results are given.