Sliding Mode Control. Switching Power Converters

Transcription

1 Sliding Mode Control of Switching Power Converters Techniques and Implementation Siew-Chong Tan Yuk-Ming Lai Chi Kong Tse Lap) CRC Press \V / Taylor & Francis Group Boca Raton London New York CRC Press is an imprint of the Taylor & Francis Group, an informa business

2 Contents 1 Introduction to Sliding Mode Control Introduction General Theory Properties of Sliding Motion An Ideal Control Practical Limitations and Chattering Constant Dynamics Quasi-Sliding Mode Control Mathematical Formulation Hitting Condition Existence Condition Stability Condition System with Linear Sliding Manifold System with Nonlinear Sliding Manifold Ideal Sliding Dynamics Equilibrium Point Linearization of Ideal Sliding Dynamics Remarks Equivalent Control Types of Implementation Relay and Signum Functions Hysteresis Function Equivalent Control Function 16 2 Overview of Power Converters and Their Control Introduction Basic DC-DC Converters Operating Modes of DC-DC Converters Overview of Control Factors Influencing Control Performances Switching Frequency Energy Storage Elements Control Gains Common Control Techniques Hysteretic Controllers Pulse-Width Modulation Controllers 28 v

3 2.6.3 Design Approaches Problems of Small-Signal Models and Compensation Control Methodologies in Research Adaptive Control Fuzzy Logic Control Artificial Neural Network Control One-Cycle Control Sliding Mode Control 33 Sliding Mode Control in Power Converters Introduction Review of Literature Earliest Works Higher-Order Converters Parallel-Connected Converters Theoretical Works Practical Works Constant Frequency SM Controllers Remarks Characteristics of SM Control as Applied to DC-DC Converters General Principle of SM Control Implementation Constant Dynamics in Power Converters Quasi-Sliding Mode Control in Power Converters Conventional Hysteresis-Modulation-Based Implementation Fixed-Frequency SM Controller in Power Converters Pulse-Width Modulation-Based Sliding Mode Controller Duty-Ratio Control Some Design Guidelines Practical Issues in Analog Implementation 51 Hysteresis-Modulation-Based Sliding Mode Controllers Introduction Theoretical Derivation Mathematical Model of Buck Converter Design of an Ideal SM Voltage Controller Design of a Practical SM Voltage Controller Redefinition of Sliding Line Introduction of Hysteresis Band Calculation of Switching Frequency A Standard Design Procedure Standard SMVC Converter Model Design Steps Step 1: Current Sensing Gain H 66

4 Vll Step 2: Voltage Divider Network ß Step 3: Gain of Differential Amplifier U v Step 4: Calculation of Hysteresis Band к Step 5: Design of Schmitt Trigger U s Experimental Results Verification of Design Equation Steady-State Performance Load Variation Line Variation a Variation ESR Variation Further Discussion Advantages Disadvantages Possible Solutions 79 Hysteresis-Modulation-Based Sliding Mode Controllers with Adaptive Control Introduction Examination of Conventional HM-Based SM Controlled Converters Mathematical Model Problems Identification Experimental Observation Analytical Explanation Possible Solutions Adaptive Feedforward Control Scheme Theory Implementation Method Adaptive Feedback Control Scheme Theory Implementation Method Experimental Results and Discussions Line Variation Load Variation 100 General Approach of Deriving PWM-Based Sliding Mode Controller for Power Converters in Continuous Conduction Mode Introduction Background The Approach System Modeling Controller Design Derivation of Existence Conditions Ill

5 Vlll Derivation of Control Equations for PWM- Based Controller Remarks Controller Structure Performance Comparison with HM-Based SM Controllers Comparing the PWM-Based SM Controller Approach to the Nonlinear PWM Controller Design Approach Load Resistance Dependence Maximum Duty Ratio Soft-Starting and Over-Current Protection Devices Simulation Results and Discussions Buck Converter Steady-State Performance Boost Converter Steady-State Performance Buck-Boost Converter Steady-State Performance 122 General Approach for Deriving PWM-Based Sliding Mode Controller for Power Converters in Discontinuous Conduction Mode Introduction State-Space Converter Model of the DC-DC Converters under DCM The Approach System Modeling Controller Design Derivation of Existence Conditions Derivation of Control Equations for PWM- Based Controller Simulation Results and Discussions Buck Converter Steady-State Performance Transient Performance Boost Converter Steady-State Performance Transient Performance Buck-Boost Converter Steady-State Performance Transient Performance Other Application of DCM SM Control: Hybrid Dual- Operating-Mode Controllers 160

6 7.5.1 Background Architecture Simulation Results and Discussions Buck Converter Boost Converter 165 Design and Implementation of PWM-Based Sliding Mode Controllers for Power Converters Introduction PWM-based SM Voltage Controller for Buck Converters Mathematical Model Existence Condition with Design Parameters Consideration Selection of Sliding Coefficients Implementation of Controller Design Procedure Parameters of Controllers Parameters of 10 khz Bandwidth Controller Parameters of 20 khz Bandwidth Controller Parameters of Adaptive FeedForward Ramp Generator Results and Discussions Steady-State Performance Load Variation Analysis Line Variation Analysis Dynamic Performance A Comparison with Classical PWM Voltage- Mode Controller PWM-Based SM Voltage Controller for Boost Converters Mathematical Model Implementation of Controller Control Signal Computation Bandwidth of Ramp Voltage Generator Duty-Ratio Protection Experimental Prototype Experimental Results and Discussions Measured Signals Ensuring Duty-Ratio Protection Testing of Variable Ramp Signal Generation Control Signals at Different Input Voltage Regulation Performance Performance Comparison with Peak Current- Mode Controller Operation in Discontinuous Conduction Mode 202 IX

7 X 9 Sliding Mode Control with a Current Controlled Sliding Manifold Introduction The Need for Current-Mode Control in Boost-Type Converters Sliding Mode Current Controller Generating a Suitable Reference Current Profile Sliding Surface Dynamical Model of Controller/Converter System and Its Equivalent Control Architecture of Controller Existence Condition Stability Condition Ideal Sliding Dynamics Equilibrium Point Analysis Linearization of Ideal Sliding Dynamics An Empirical Approach of Selecting the Sliding Coefficients Additional Remarks Results and Discussions Regulation Performance Dynamic Performance Sliding Mode Control with a Reduced-State Sliding Manifold for High-Order Converters Introduction Review of Conventional Sliding Mode Controllers for Cuk Converters State-Space Model of Cuk Converter Full-State SM Controller Reduced-State SM Controller Voltage-Mode Control SM Controller Current-Mode Control SM Controller Constant-Frequency Reduced-State Sliding Mode Current Controller Sliding Surface Dynamical Model of Controller/Converter System and Its Equivalent Control Architecture of Controller Existence Condition Stability Condition Ideal Sliding Dynamics Equilibrium Point Linearization of Ideal Sliding Dynamics Selection of Sliding Coefficients Further Comments 235

8 10.4 Results and Discussion Steady-State Performance Dynamic Performance Indirect Sliding Mode Control with Double Integral Sliding Surface Introduction Problem Identification Review of Hysteresis-Modulation-Based Sliding Mode Controllers Review of Indirect Sliding Mode Controllers Analytical Explanation for the Presence of Steady-State Error in Indirect ISM-Controlled Converter A Possible Solution Application of Double-Integral Sliding Surface to PWM-Based Types of Indirect Sliding Mode Controllers Double-Integral Sliding Mode Controllers Architecture of DISM Controllers in PWM Form Existence Condition Stability Condition Ideal Sliding Dynamics Equilibrium Point Linearization of Ideal Sliding Dynamics Results and Discussions Simulation Result of PWM-Based DISM Buck Converter Experimental Result of PWM-Based DISM Boost Converter 259 Bibliography 267 Index 279 XI