2 research outputs found
Cascade Control of PM DC Drives Via Second-Order Sliding-Mode Technique
Abstract-This paper presents a novel scheme for the speed/ position control of permanent-magnet (PM) dc motor drives. A cascade-control scheme, based on multiple instances of a secondorder sliding-mode-control (2-SMC) algorithm, is suggested, which provides accurate tracking performance under large uncertainty about the motor and load parameters. The overall control scheme is composed of three main blocks: 1) a 2-SMC-based velocity observer which uses only position measurements; 2) a 2-SMC-based velocity control loop that provides a reference command current; and 3) a 2-SMC-based current control loop generating the reference voltage. The proposed scheme has been implemented and tested experimentally on a commercial PM dc motor drive. The experimental results confirm the precise and robust performance and the ease of tuning and implementation, featured by the proposed scheme. Index Terms-Cascade control, dc motor drives, second-order sliding-mode (2-SM) control (2-SMC), SM differentiators
An approach to design of digital sliding mode control for DC-DC converters
The primary goal of research in this Ph.D. dissertation is to investigate the possibilities of
application of modern control methods in controlling the output voltage of the DC-DC
converters (buck, boost) in order to ensure the system robustness to the input voltage and load
variations. This dissertation deals with the analysis and application of sliding mode control
algorithms in the synthesis of these converters in order to improve the properties of existing
converters and to modify them, as well as to adjust and tune the digital sliding mode controls
based on the input-output plant model to be applicable in these converters.
The design procedure is based on the converter models given in the form of discrete transfer
functions. The proposed control for converters is a combination of the digital sliding mode
control and (generalized) minimum variance control techniques. The problem caused by an
unstable zero of the boost converter, which prevents the direct control of the output voltage of
this converter, has been overcome by introducing the generalized minimum variance control.
Also, only the output voltage of converter must be measured for the realization of the proposed
control, so there is no need for an additional current sensor. This dissertation includes the
modification of the developed algorithms with the aim of applying them to low-cost, standard 8-
bit microcontrollers.
Finally, the efficiency of the proposed solutions is verified by digital simulation and a series
of experiments on the laboratory developed prototypes of both converters, as well as by their
comparative analysis. The satisfactory experimental results are obtained regarding the typical
characteristics of the converters