WILEY CONTROL OF POWER INVERTERS IN RENEWABLE ENERGY AND SMART GRID INTEGRATION. Qing-Chang Zhong. Tomas Hornik IEEE PRESS

Transcription

1 CONTROL OF POWER INVERTERS IN RENEWABLE ENERGY AND SMART GRID INTEGRATION Qing-Chang Zhong The University of Sheffield, UK Tomas Hornik Turbo Power Systems Ltd., UK WILEY A John Wiley & Sons, Ltd., Publication IEEE PRESS

2 Preface Acknowledgments About the Authors List of Abbreviations xvii xix xxi xxiii 1 Introduction Outline of the Book Basics of Power Processing J AC-DC Conversion DC-DC Conversion DC-AC Conversion AC-AC Conversion Hardware Issues Isolation Power Stages Output Filters Voltage and Current Sensing Signal Conditioning Protection Central Controller Test Equipment Wind Power Systems Basics of Wind Power Generation Wind Turbines Generators and Topologies Control of Wind Power Systems Solar Power Systems Introduction to Solar Power Processing of Solar Power Smart Grid Integration Operation Paradigms of Power Systems Introduction to Smart Grids Requirements for Smart Grid Integration 59

3 viii Contents 2 Preliminaries Power Quality Issues Introduction Degradation Mechanisms of Voltage Quality Role of Inverter Output Impedance Repetitive Control Basic Principles Poles of the Internal Model M(s) Selection of the Delay in the Internal Model Reference Frames Natural (abc) Frame Stationary Reference (aft) Frame Synchronously Rotating Reference (dq) Frame The Case with Phase Sequence acb 76 PART I POWER QUALITY CONTROL 3 Current H Repetitive Control System Description Controller Design State-space Model of the Control Plant P Formulation of the Standard H00 Problem Evaluation of the Systan Stability Design Example Experimental Results Synchronisation Process Steady-state Performance Transient Response (without a Load) Summary 91 4 Voltage and Current H Repetitive Control System Description Modelling of an Inverter Controller Design Formulation of the H Control Problem Realisation of the Generalised Plant State-space Realisation of Tew State-space Realisation oft/,a Design Example Simulation Results Nominal Responses Response to Load Changes, Response to Grid Distortions Summary 107

4 5 Voltage H Repetitive Control with a Frequency-adaptive Mechanism System Description Controller Design State-space Model of the Control Plant P Frequency-adaptive Internal Model M Formulation of the Standard H Problem Evaluation ofsystem Stability Design Example Experimental Results Steady-state Performance in the Stand-alone Mode Steady-slate Performance in the Grid-connected Mode Transient Response: without a Local Load Response to Variations of the Grid Frequency Summary Cascaded Current-Voltage H Repetitive Control Operation Modes in Microgrids Control Scheme Design of the Voltage Controller State-space Model of the Plant Pu Formulation of the Standard H Problem Design of the Current Controller State-space Model of the Plant Pt Formulation of the Standard H Problem Design Example Design of the H Voltage Controller Design of the H Current Controller Experimental Results Steady-state Performance in the Stand-alone Mode Steady-state Performance in the Grid-connected Mode Transient Performance Seamless Transfer of the Operation Mode Summary Control of Inverter Output Impedance Inverters with Inductive Output Impedances (L-inverters) Inverters with Resistive Output Impedances (R-inverters) Controller Design Stability Analysis Inverters with Capacitive Output Impedances (C-inverters) Design of C-inverters to Improve the Voltage THD General Case Special Case I: to Minimise the 3rd and 5th Harmonic Components Special Case II: to Minimise the 3rd Harmonic Component Special Case III: to Minimise the 5th Harmonic Component 157

5 7.5 Simulation Results for R-, L- and C-inverters The Case with L = 2.35 mh The Case with L = 0.25 mh Experimental Results for R-, L- and C-inverters The Case with L = 2.35 mh The Case with L = 0.25 mh Impact of the Filter Capacitor Summary Bypassing Harmonic Current Components Controller Design Physical Interpretation of the Controller Stability Analysis Without Consideration of the Sampling Effect With Consideration of the Sampling Effect Experimental Results Summary Power Quality Issues in Traction Power Systems Introduction Description of the Topology Compensation of Negative-sequence Currents, Reactive Power and Harmonic Currents Grid-side Currents before Compensation Compensation of Active and Reactive Power Compensation of Harmonic Currents Regulation of the DC-bus Voltage Implementation of the Compensation Strategy Special Case: cos 0 = Simulation Results The Case when cos 6 ^ The Case when cos 9 = Summary 184 PART II NEUTRAL LINE PROVISION 10 Topology of a Neutral Leg Introduction Split DC Link Conventional Neutral Leg Independently-controlled Neutral Leg Summary Classical Control of a Neutral Leg Mathematical Modelling Controller Design 195

6 Design ofthe Current Controller K, Design ofthe Voltage Controller Kv Performance Evaluation Selection of the Components Capacitor CN Inductor LN Simulation Results WithiN 0 = With a 50 Hz Neutral Current With a 150 Hz Neutral Current With a DC Neutral Current Summary H Voltage-Current Control of a Neutral Leg Mathematical Modelling Controller Design / State-space Realisation of P State-space Realisation of the Closed-loop Transfer Function Selection of Weighting Functions Design Example Simulation Results Summary Parallel PI Voltage-//00 Current Control of a Neutral Leg Description of the Neutral Leg Design of an H Current Controller Controller Description Formulation as a Standard H Problem State-space Realisation of the Plant P State-space Realisation of the Generalised Plant P Design Example Addition of a Voltage Control Loop Experimental Results Steady-state Performance Transient Response to Changes in the Neutral Current Summary Applications in Single-phase to Three-phase Conversion Introduction The Topology under Consideration Basic Analysis Controller Design Synchronisation Unit Control of the Rectifier Leg Control of the Neutral Leg Control of the Phase Legs 242

7 xii Contents 14.5 Simulation Results With Three-phase Linear Balanced Loads With Three-phase Non-linear Unbalanced Loads Summary 248 PART III POWER FLOW CONTROL 15 Current Proportional-Integral Control Control Structure In the Synchronously Rotating Reference (dq) Frame Equivalent Structure in the Natural (abc) Frame Controller Implementation Experimental Results Steady-state Performance Transient Performance Summary Current Proportional-Resonant Control Proportional-resonant Controller Control Structure In the Stationary Reference (afi) Frame Equivalent Controller in the abc Frame Controller Design Model of the Plant Design Example Experimental Results Steady-state Performance Transient Performance Summary Current Deadbeat Predictive Control Control Structure Controller Design Experimental Results Steady-state Performance Transient Performance Summary Synchronverters: Grid-friendly Inverters that Mimic Synchronous Generators Mathematical Model of Synchronous Generators Electrical Part Mechanical Part Presence of a Neutral Line 281

8 xiii 18.2 Implementation of a Synchronverter Power Part Electronic Part Operation of a Synchronverter Regulation ofreal Power and Frequency Droop Control Regulation ofreactive Power and Voltage Droop Control Simulation Results Under Different Grid Frequencies Under Different Load Conditions Experimental Results Performance of Power Flow Control Loading Performance in the Stand-alone Mode Loading Performance in the Grid-connected Mode Summary Parallel Operation of Inverters Introduction Problem Description Power Delivered to a Voltage Source Conventional Droop Control For R-inverters For L-inverters For C-inverters Experimental Results with R-inverters Inherent Limitations of Conventional Droop Control Real Power Sharing Reactive Power Sharing Robust Droop Control of R-inverters Control Strategy Error Due to Inaccurate Voltage Measurements Voltage Regulation Error Due to the Global Settingsfor E* and co* Experimental Results Robust Droop Control of C-inverters Control Strategy Simulation Results J Experimental Results Robust Droop Control of L-inverters Control Strategy Simulation Results Experimental Results Summary 20 Robust Droop Control with Improved Voltage Quality Control Strategy Experimental Results 337

9 xiv Contents : 1 Power Sharing : 1 Power Sharing Summary Harmonic Droop Controller to Improve Voltage Quality Model of an Inverter System Power Delivered to a Current Source Reduction of Harmonics in the Output Voltage Simulation Results Experimental Results Summary 358 PART IV SYNCHRONISATION 22 Conventional Synchronisation Techniques Introduction Zero-crossing Method Basic Phase-locked Loops (PLL) PLL in the Synchronously Rotating Reference Frame (SRF-PLL) Second-order Generalised Integrator-based PLL (SOGI-PLL) Sinusoidal Tracking Algorithm (STA) Simulation Results with SOGI-PLL and STA With a Noisy Distorted Signal having a Variable Frequency With a Noisy Distorted Square Wave Experimental Results with SOGI-PLL and STA With a Voltage Taken from the Grid With a Noisy Distorted Signal having a Variable Frequency With a Noisy Distorted Square Wave Summary Sinusoid-locked Loops Single-phase Synchronous Machine (SSM) Connected to the Grid Structure of a Sinusoid-locked Loop (SLL) Tracking of the Frequency and the Phase Tracking of the Voltage Amplitude Tuning of the Parameters Equivalent Structure Simulation Results With a Noisy Distorted Signal having a Variable Frequency With a Noisy Distorted Square Wave Experimental Results With a Voltage Taken from the Grid 386

10 xv With a Noisy Distorted Signal having a Variable Frequency With a Noisy Distorted Square Wave Summary 390 References Index