Design of robust controllers for telecom power supplies
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Doctoral thesis (article-based)
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Author
Date
2002-10-11
Major/Subject
Mcode
Degree programme
Language
en
Pages
84, [100]
Series
Report / Helsinki University of Technology, Control Engineering Laboratory, 132
Abstract
A Telecom power supply is studied and analyzed from control system viewpoint. It consists of three stages: AC/DC rectifier, a backup battery, and a Telecom load. The AC/DC rectifier stage can be composed of paralleled DC/DC converters preceded by paralleled AC/DC converters. However, paralleled DC/DC converters are only considered in this thesis because they constitute the main dynamics in practice. A system of paralleled DC/DC converters operating in continuous inductor current mode with either voltage mode control or peak current mode control are modeled and analyzed using state-space representation. The H∞ control design is used in order to guarantee the robust stability and robust performance of the system in spite of different uncertainties. Also the H∞ loop-shaping design is used to design robust controllers in the presence of uncertainties. μ-analysis is used to evaluate the robustness of the system. Simulation results are presented to demonstrate the control design procedure and to compare between the two approaches presented. A Telecom power system can be composed of voltage-loop and current-loop subsystems. The multi-input-multi-output proportional-integral-derivative (PID) controller is first designed achieving robust stability and robust performance of the voltage-loop. Then, the multi-input-multi-output proportional-integral (PI) controller for current-loop is designed to achieve robust stability and robust performance of the overall system. μ-analysis is used to evaluate the robustness of PID and PI controllers. Simulation results are also presented to demonstrate and validate the control design. The required output characteristic of a Telecom power system contains three modes of operation: constant-voltage, modified constant-power, and constant-current modes. This nonlinear operation can be achieved by using the fuzzy-logic approach. A fuzzy PID-like controller is implemented to achieve the robust output voltage in spite of load disturbances. A fuzzy PI-like controller is implemented to ensure the overload protection reaching the optimal output characteristic of a Telecom power system. Also the internal-model control (IMC) method is applied to basic DC/DC converters: buck, boost, and buck-boost converters. IMC scheme is used to improve the dynamic performance of basic converters by achieving a robust output voltage against line and load disturbances. Simulations show good dynamic performance of the IMC controller.Description
Keywords
telecom power supply, H<sub>∞</sub> control, PID-control, fuzzy-logic control, internal-model control
Other note
Parts
- Gadoura, I., T. Suntio, and K. Zenger. Robust Control Design for Paralleled DC/DC Converters with Current Sharing. Proc. of the 15th IFAC World Congress on Automatic Control, July 21-26, 2002 in Barcelona, Spain, 6p, CD-ROM.
- Gadoura, I., T. Suntio, and K. Zenger. Dynamic System Modeling and Analysis for Multiloop Operation of Paralleled DC/DC Converters. Proc. of the Int. Con. on Power Electronics and Intelligent Motion, June 19-21, 2001 in Nuremberg, Germany, pp. 443-448.
- Gadoura, I., T. Suntio, and K. Zenger. Model Uncertainty and Robust Control of Paralleled DC/DC Converters. Proc. of the IEE Int. Con. of Power Electronics, Machines, and Drives, April 16-18, 2002 in Bath, UK, pp. 74-79.
- Gadoura, I., T. Suntio, and K. Zenger. Practical Robust Control Design for Paralleled DC/DC Converters using H<sub>∞</sub> Loop-Shaping Techniques. Proc. of the Int. Con. on Power Electronics and Intelligent motion, May 14-16, 2002 in Nuremberg, Germany, pp. 335-340.
- Suntio, T., I. Gadoura, J. Lempinen, and K. Zenger. Practical Design Issues of Multi-loop Controller for a Telecom Rectifier. Proc. of the IEEE Int. Telecommunications Energy Special Conference, May 07-10, 2000 in Dresden, Germany, pp. 197-201.
- Gadoura, I., and T. Suntio. Implementation of Optimal Output Characteristic for a Telecom Power Supply: Fuzzy-logic Approach. International Journal of Control and Intelligent Systems, 2002 (in press).
- Gadoura, I., T. Suntio, K. Zenger, and P. Vallittu. Internal Model Control for DC/DC Converters. Proc. of the 8th European Con. on Power Electronics and Applications, September 7-9, 1999, Lausanne, Switzerland, 7p, CD-ROM.
- Gadoura, I., T. Suntio, and K. Zenger. Improved Stability Properties of Boost and Buck-boost Converters Using IMC-based Controller. Proc. of the Int. Con. on Power Electronics and Intelligent Motion, June 19-21, 2001 in Nuremberg, Germany, pp. 527-532.