A comparison of simulation and hardware-in-the-loop alternatives for digital control of power converters

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. A. Sánchez, Á. de Castro, J. Garrido, "A Comparison of Simulation and Hardware-in-the- Loop Alternatives for Digital Control of Power Converters", IEEE Transactions on Industrial Informatics, vol. 8, no. 3, pp. 491 - 500, Aug. 2012Debugging digital controllers for power converters can be a problem because there are both digital and analog components. This paper focuses on debugging digital controllers to be implemented in Field Programmable Gate Arrays or Application Specific Integrated Circuits, which are designed in hardware description languages. Four methods are proposed and described. All of them allow simulation, and two methods also allow emulation-synthesizing the model of the converter to run the complete closed-loop system in actual hardware. The first method consists in using a mixed analog and digital simulator. This is the easiest alternative for the designer, but simulation time can be a problem, specially for long simulations like those necessary in power factor correction or when the controller is very complex, for example, with embedded processors. The alternative is to use pure digital models, generating a digital model of the power converter. Three methods are proposed: real type, float type and fixed point models (in the latter case including hand-coded and automatic-coded descriptions). Float and fixed point models are synthesizable, so emulation is possible, achieving speedups over 20 000. The results obtained with each method are presented, highlighting the advantages and disadvantages of each one. Apart from that, an analysis of the necessary resolution in the variables is presented, being the main conclusion that 32-bit floating point is not enough for medium and high switching frequencies

Modeling of power converters for debugging digital controllers through FPGA emulation

Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. F. Lopez-Colino, A. Sanchez, A. de Castro, and J. Garrido, "Modeling of power converters for debugging digital controllers through FPGA emulation", in 15th European Conference on Power Electronics and Applications (EPE), 2013.Debugging a digital controller for power converters can be a lengthy process due to the long time required in mixed-signal simulations. This paper focuses on the design of a power converter model for debugging digital controllers in closed loop. The testing may be performed by means of simulation or emulation. This paper shows the results of simulating and emulating the power converter using different data representations. Experiments will show that through a good selection of data and emulation, testing can be speeded up over 28,000 times.This work has been partially supported by the Spanish Ministerio de Ciencia e Innovacion under project TEC2009-09871

Impact of the hardened floating-point cores on HIL technology

The Hardware-In-the-Loop (HIL) technique is increasingly used for testing power electronics. FPGAs (Field-Programmable Gate Array) are becoming usual in this kind of emulation due to their acceleration capabilities. But even using FPGAs, it has not been possible to reach real time simulations when small integration steps are necessary (around 100 ns or lower) if floating-point representation is used. Fixed-point has been the solution, but at a high design effort cost. With the release of FPGAs with HFP (Hardened Floating-Point) cores – dedicated floating-point blocks implemented in silicon – the minimum achievable simulation step decreases significantly. This paper presents a comparison between HFP cores, floating-point in programmable logic and fixed-point for HIL models. Results show that both HFP-based and fixed-point arithmetic achieve a simulation step around 10 ns for a full-bridge converter model. A comparison regarding resolution and accuracy is also presented, because acceleration is not the only issue when decreasing the integration step. Numerical resolution also plays an important role, and 32-bit floating-point representation finds a double barrier: acceleration marked by technology, and numerical resolution. Both are explored in this paperThis work has been supported by the Spanish Ministerio deEconomía y Competitividad under project TEC2013-43017-

Design and Control of Power Converters 2019

In this book, 20 papers focused on different fields of power electronics are gathered. Approximately half of the papers are focused on different control issues and techniques, ranging from the computer-aided design of digital compensators to more specific approaches such as fuzzy or sliding control techniques. The rest of the papers are focused on the design of novel topologies. The fields in which these controls and topologies are applied are varied: MMCs, photovoltaic systems, supercapacitors and traction systems, LEDs, wireless power transfer, etc

Measurements, Models, Systems and Design

531 s.

Review on decomposed fuzzy PID structure for power inverters regulation

The aim of this paper is to critically review prominent decomposed Fuzzy PID control structures. Structural construction and output control laws of these controllers will be discussed. Their merits and drawbacks are highlighted. Based on the critical discussions, a new structure of Fuzzy PID controller is proposed. It is based on cascaded structure, which yields simpler design flow and parameters tuning. Other advantages of the proposed Fuzzy PID structure are the reduction of tuning parameters and rules of the Fuzzy controller. In addition, the proposed structure allows the usage of signed distance method. The application of the method reduces the computation burden significantly as the power inverter regulation needs very fast and precise computation

MATLAB

A well-known statement says that the PID controller is the "bread and butter" of the control engineer. This is indeed true, from a scientific standpoint. However, nowadays, in the era of computer science, when the paper and pencil have been replaced by the keyboard and the display of computers, one may equally say that MATLAB is the "bread" in the above statement. MATLAB has became a de facto tool for the modern system engineer. This book is written for both engineering students, as well as for practicing engineers. The wide range of applications in which MATLAB is the working framework, shows that it is a powerful, comprehensive and easy-to-use environment for performing technical computations. The book includes various excellent applications in which MATLAB is employed: from pure algebraic computations to data acquisition in real-life experiments, from control strategies to image processing algorithms, from graphical user interface design for educational purposes to Simulink embedded systems

AUTONOMOUS DC MICROGRID WITH SELF-CONFIGURABLE FEASIBILITY

Microgrids are power systems that work not only from the main power grid, but also in island mode operation. As each of the power sources and loads have voltage and current limitations, the autonomous microgrid should be able to control voltage and current levels while loads and sources are connected to the grid. Therefore, the microgrid bus voltage remains constant and power transfers safely. To configure an autonomous microgrid, the load and source type identification comes to mind. An autonomous microgrid needs to know the type of the electrical components which are going to be connected to the grid. In this study, by using voltage trend recognition, the type of the electrical device (DC power supply, battery, and load) is identified. Moreover, by recognizing the battery state of charge (SOC), the electrical power management of the microgrid is optimized. The experimental setup is able to detect the type of the electrical device (battery, voltage source or load) and then configures the DC microgrid to transfer power efficiently. By implementing PI controller and fuzzy method to control the DC microgrid, various cases in the microgrid such as load sharing, charging the battery, powering the different loads (uncharged battery, DC motor, and resistive loads) and importing new sources and xi loads are used to test the experimental setup of the DC microgrid and related power electronics converters. The experimental results demonstrate the validity and efficiency of the proposed system for the self-configurable autonomous DC microgrid