Training structure:
The duration of the training is 2 days.
Training objective:
The objective of the training is to acquire the basic abilities about controller design for voltage source converters. Starting with a basic study of the control problem, the more important control structures will be covered together the main aspects to be into account in the digital implementation. Design procedures based on software tools like PSIM and SmartCtrl will be applied and illustrated through practical design cases.
Intended audience:
The training course is recommended to everybody interested in the theoretical aspects and practical design issues of digital control of voltage source converters. Having previous experience in power electronics and circuit simulation is useful, but beginners with no background in those topics will also benefit from the training.
Topics:
Day 1:
- Section I: Modulation techniques in DC/AC converters
- Inverter concepts and inverter topologies
- Basic Output Voltage Control
- Square wave operation
- Phase Shift Modulation
- Fundamentals of PWM modulation
- Unipolar Sinusoidal PWM Modulation
- Bipolar Unipolar Sinusoidal PWM Modulation
- 3-ph PWM modulation
- Practical considerations
- Advanced Modulation Techniques
- Third-Harmonic Injection PWM
- Space Vector Modulation
- Selective Harmonic Elimination
- Section II: Single-Phase Voltage-Source Inverter
- Problem Specifications
- Current Control
- Average Model and Small Signal Model
- Feed-Forward
- PI Design
- Digital Current Control
- Signal conditioning and sampling
- Synchronization between sampling and PWM
- Discretization strategies of PI controllers
- Origin and effect of digital delay
- Voltage Control
- Average Model and Small Signal Model
- Feed-Forward
- PI Design
- PSIM Simulation results
- ANNEX A, B: SmartCtrl Equation Editor Code
- Section III: Three-Phase Grid-Tied Voltage-Source Inverter
- Space Phasors and Two-Dimensional Frames
- Fundamentals through PSIM simulations
- Dq Current Control of Grid-Tied Inverter
- Average and Small-Signal Models of L filter
- Average and Small-Signal Models of LCL filter
- Feed-Forward Compensations
- Design with SmartCtrl
- PSIM simulation
- Alfa-Beta Current Control of Grid-Tied Inverter
- Comparison with dq Control
- Resonant Controllers
- Design with SmartCtrl
- PSIM simulation
- Digital Implementation of the Current Control
- Signal conditioning and sampling
- Synchronization between sampling and PWM
- Discretization strategies of PI and resonant controllers
- Effect of digital delay
- Design with SmartCtrl
- PSIM simulations
- DC BUS Voltage Control
- Average Model
- Small-Signal Model
- Feed-Forward Compensations
- Design with SmartCtrl
- PSIM simulations
- Section IV: Grid-Synchronization in Three-Phase Power Converters
- Introduction
- Grid Codes
- Grid-Synchronization Fundamentals.
- PLL Tecniques
- Instant Alfa – Beta PLL
- Synchronous Reference Frame PLL (SRF PLL)
- Sequence detector based on Second-Order Generalized Integrator (SOGI)
- SOGI-SRF PLL
- Design with SmartCtrl
- PSIM simulations
Day 2:
- Section V: Three-Phase Voltage-Source Inverter (AC Voltage Generation)
- Average Model
- Small-Signal Model
- Control Loops Design with SmartCtrl
- Inner Loop Frequency response validation with PSIM´s AC sweep
- Outer Loop Frequency response validation with PSIM´s AC sweep
- Influence of the Current Sensing Strategies
- Section VI: Complete digital design of Three-Phase Grid-Tied Voltage-Source Inverter: SmartCtrl design PSIM simulation and HW experiments
- Description of the hardware set up: Three-Phase Grid-Tied Voltage-Source Inverter and SoC based digital control
- SoC control parametrization with SmartCtrl Console
- Experiments: voltage steps, reference steps, load steps, etc.
Methodology:
The overall methodology is based on theoretical explanation on main concepts and details followed by practical implementation of the complete design procedure: controller design by means of SmartCtrl, PSIM simulations and hardware validation by means of a scale – down prototype.
- 60% theoretical contents
- 20% practical exercises by means of guided PSIM simulations and SmartCtrl designs
- 10% exercises using a hardware demonstrator
A complete set of SmartCtrl and PSIM exercises already developed will be provided to the audience together with the rest of course materials. During practical exercises, attendees will be asked to change some component values and/or modify the schematics of the provided examples and carry out simulations. For hardware experiments SmartCtrl Console will be used to modify control parameters of a digitally controlled three-phase PFC. Attendees will experiment different effects of the digital control design by means of reference and output current step changes.
