Search

In this paper, an attempt is made to improve the performance of permanent magnet DC (PMDC) motor using third order sliding mode control. From the derived mathematical modelling for buck converter fed permanent magnet DC motor, expressions for both classical sliding surface (CSS) and proportional integral derivative sliding surface (PIDSS) with the third order sliding mode control is derived and compared analytically. Simulation work is done for PI controller, sliding mode control (SMC), third order CSS and third order PIDSS by using Matlab/Simulink to validate the performance of the above said controllers under no-load condition and various load torque conditions such as: constant load torque, frictional load torque, fan type load torque, propeller type load torque and undefined load torque. Experimental results are obtained with PMDC motor to validate the proposed control method for various speeds with different constant load torque conditions. Comparisons are carried out both in simulation and real time for PI controller, SMC, CSS and PIDSS based on the speed settling time and steady state error. Satisfactory results are obtained and presented in this paper.

In this paper, passivity-based control (PBC) of a Luo converter-fed DC motor is implemented and presented. In PBC, both exact tracking error dynamics passive output feedback control (ETEDPOF) and energy shaping and damping injection methods do not require a speed sensor. As ETEDPOF does not depend upon state computation, it is preferred in the proposed work for the speed control of a DC motor under no-load and loaded conditions. Under loaded conditions, the online algebraic approach in sensorless mode (SAA) is used for estimating different load torques applied on the DC motor such as: constant, frictional, fan-type, propeller-type and unknown load torques. Performance of SAA is tested with the reduced order observer in sensorless mode (SROO) approach and analyzed, and the results are presented to validate the low-cost implementation of PBC for a DC drive without a speed and torque sensor.

Multilevel inverter had been paid a lot of attention from the academia and research community in recent times due to its role in high and medium power applications. In this paper, a detailed survey is made on the recently designed multilevel inverter to find the suitability of the inverters for particular applications. Research is performed on various types of multilevel inverters such as: Symmetric, asymmetric, hybrid and modularized multilevel inverter in order to identify the issues in generating more levels at the output. A summary of various issues in multilevel inverter with reduced switch count is provided, so that a novel topology of multilevel inverter can be designed in future. Further, an 81-level switched ladder multilevel inverter using unidirectional and bidirectional switches is designed. Simulation work is carried out using Matlab/Simulink in order to validate the performance of the inverter with change in resistive load and impedance load. The output of the 81-level inverter is fed to a 110 V, 186.5 W single phase induction motor in order to study the characteristics, further speed control of motor is performed by varying the input voltage of the motor and the results are presented.

In this paper, a ‘k’-state inverter producing a higher number of voltage levels was designed, and we studied the inverter’s working. Further, a tri-state inverter was derived from the ‘k’-state inverter, which could build a maximum number of output voltage levels with the requirement of fewer components, thereby reducing the cost and size. A single Tri-state architecture generates three direct current (D.C.) voltage levels; therefore, cascading five tri-state architectures can generate 242 levels of DC voltages. Further, the inversion is done via the H bridge, which leads to 485 levels of the output voltage. Algorithms to design the amplitude of voltage sources and the generation of pulses are discussed in this paper. The proposed tri-state inverter takes a significant role in advancing renewable energy systems in utilizing inverter technology. A simulation study validated the operation of the proposed inverter. Moreover, an experimental setup was built for a single-phase 485-level inverter, and the structure’s performance was verified through the experimental results.

In this paper, identification of sensitive variables is attempted for second-order (flat/partially flat) and fourth-order partially flat converters with dynamic loads. The sensitivity nature of each state variable to the output speed variable of the DC motor for the above-mentioned systems was analyzed via the frequency domain technique. Further, in continuation of this, we aimed to confirm that the variables that are used in the control law exact tracking error dynamics, passive output feedback control (ETEDPOF) are sensitive. To verify the sensitivity property, an experimental case study was done using ETEDPOF and compared with the proportional-integral controller (PIC) for a flat system, and the results are presented.