Nonsingular terminal sliding mode control for the speed regulation of permanent magnet synchronous motor with parameter uncertainties

The drive performance of permanent magnet synchronous motor (PMSM) can be deteriorated due to various disturbances. In this paper, the problem of speed control for a PMSM system with parameter uncertainties is investigated. A new control algorithm based on nonsingular terminal sliding mode control (NTSMC) is proposed, where the controller is developed for speed regulation. Compared with conventional strategies, this new controller provides improved performance for speed regulation of PMSM when subject to parameter uncertainties, in that it achieves fast dynamic response and strong robustness. Simulation studies are conducted to verify the effectiveness of this proposed method

A New Fixed Switching Frequency Direct Torque Controlled PMSM Drives with Low Ripple in Flux and Torque

Direct Torque Control (DTC) has gained popularity for development of advanced motor control due to its simplicity and offers fast instantaneous torque and flux controls. However, the conventional DTC which is based on hysteresis controller has major drawbacks, namely high torque ripple and variable inverter switching frequency. This paper presents an improved switching strategy for reducing flux and torque ripples in DTC of PMSM drives; wherein the torque hysteresis controller and the look-up table used in the conventional DTC are replaced with a constant frequency torque controller (CFTC) and an optimized look-up table, respectively. It can be shown that a constant switching frequency is established due to the use of the CFTC while the reduction of torque and flux ripples is achieved mainly because of the selection of optimized voltage vector (i.e. with an optimized look-up table). This paper also will explain the construction of DTC schemes implemented using MATLAB-Simulink blocks. Simulation results were shown that a significant reduction of flux and torque ripples which is about 90% can be achieved through the proposed DTC scheme

A New Fixed Switching Frequency Direct Torque Controlled PMSM Drives with Low Ripple in Flux and Torque

Direct Torque Control (DTC) has gained popularity for development of  advanced  motor  control  due  to  its  simplicity  and  offers  fast  instantaneous torque  and  flux  controls.  However,  the  conventional  DTC  which  is  based  on hysteresis  controller  has  major  drawbacks,  namely  high  torque  ripple  and variable  inverter  switching  frequency.  This  paper  presents  an  improved switching strategy for reducing flux and torque ripples in DTC of PMSM drives; wherein  the  torque  hysteresis  controller  and  the  look-up  table  used  in  the conventional  DTC  are  replaced  with  a  constant  frequency  torque  controller (CFTC)  and  an  optimized  look-up  table,  respectively.  It  can  be  shown  that  a constant switching frequency is established due to the use of the CFTC while the reduction of torque and flux ripples is achieved mainly because of the selection of optimized  voltage  vector (i.e.  with an optimized  look-up  table).  This paper also  will  explain  the  construction  of  DTC  schemes  implemented  using MATLAB-Simulink  blocks.  Simulation  results  were  shown  that  a  significant reduction of flux and torque ripples which is about 90% can be achieved through the proposed DTC scheme.

Quantified Design Guidelines of Compact Active EMI Filters to Reduce the Common-Mode Conducted Emissions

Department of Electrical EngineeringIn switching mode power supplies (SMPS), noise currents induced by the switching operation travel along the input power line and may, in turn, cause interference with other electronic systems, including the SMPS???s auxiliary circuit. The noise current, caused by the switching operation to convert the voltage, is the main source of the conducted emissions. The passive EMI filters (PEFs) composed of a common mode (CM) chokes, Y-capacitors, and X-capacitor are generally used to suppress the conducted emissions. However, the CM chokes are bulky and occupy a lot of room. Y-capacitors cause the undesired touch current flowing from the power lines to the earth GND. In this thesis, three types of active EMI filters (AEF) ??? 1) voltage-sense voltage compensation (VSVC); 2) voltage-sense current-compensation (VSCC); 3) current-sense current-compensation (CSCC) ??? have been proposed to help overcome the limitation of the PEFs. The proposed AEFs have been designed as the feed-forward or transformerless configurations to manufacture in the compact size. Each AEF is completely analyzed by using the equivalent circuit model. Based on the rigorous analysis, the design guidelines of each AEF are established. In the design guidelines, the practical issues regarding the stability and high-voltage immunity are also considered. The performance of each AEF is validated through the experiments using a vector network analyzer (VNA) and the CM-conducted emissions measurements. The feed-forward VSVC AEF is designed in a compact package to suppress CM-conducted emissions. The power line impedance is enlarged by the VSVC AEF and verified through the measurement. The VSVC AEF was installed in a 200W switching mode power supply (SMPS) board with 64 kHz and 110 kHz switching frequencies, demonstrating its usefulness by experiments. The performance degradation due to the magnetic saturation and the AEF grounding impedance was also analyzed and investigated The transformerless VSCC AEF is developed to avoid the degradation due to the magnetic saturation. The sensing and compensation part is realized by only the capacitors, and the push???pull amplifier is utilized to generate the compensation signal corresponding to the sensed noise. Furthermore, the protection circuits against the high-voltage transient are developed and applied into the AEF. The VSCC AEF is then implemented into a real 2.2 kW current resonant inverter, and the conducted emissions are reduced by 5dB to 25 dB at a frequency range from 150 kHz to 6 MHz. In addition, the AEF???s immunity against high-voltage transients is demonstrated by lightning surge tests. The CSCC AEF is designed as the symmetric structure using the capacitive coupling. The transformer with a small number of turns is utilized for the sensing transformer to avoid degradation due to the magnetic saturation. The CSCC AEF is also designed using the proposed design guidelines and employed into the real product. In the CM conducted emissions measurement, the CSCC AEF shows 5~20 dB noise attenuation from 150 kHz to 10 MHz. The degradation of the CSCC AEF due to the asymmetric structure is investigated by using the VNA measurements.ope