Computer-Aided Design of Digital Compensators for DC/DC Power Converters

Digital control of high-frequency power converters has been used extensively in recent years, providing flexibility, enhancing integration, and allowing for smart control strategies. The core of standard digital control is the discrete linear compensator, which can be calculated in the frequency domain using well-known methods based on the frequency response requirements (crossover frequency, f c , and phase margin, PM ). However, for a given compensator topology, it is not possible to fulfill all combinations of crossover frequency and phase margin, due to the frequency response of the controlled plant and the limitations of the compensator. This paper studies the performance space ( f c , PM ) that includes the set of achievable crossover frequencies and phase margin requirements for a combination of converter topology, compensator topology, and sensors, taking into account the effects of digital implementation, such as delays and limit cycling. Regarding limit cycling, two different conditions have been considered, which are related to the design of the digital compensator: a limited compensator integral gain, and a minimum gain margin. This approach can be easily implemented by a computer to speed up the calculations. The performance space provides significant insight into the control design, and can be used to compare compensator designs, select the simplest compensator topology to achieve a given requirement, determine the dynamic limitations of a given configuration, and analyze the effects of delays in the performance of the control loop. Moreover, a figure of merit is proposed to compare the dynamic performance of the different designs. The main goal is to provide a tool that identifies the most suitable compensator design in terms of the dynamic performance, the complexity of the implementation, and the computational resources. The proposed procedure to design the compensator has been validated in the laboratory using an actual DC/DC converter and a digital hardware controller. The tests also validate the theoretical performance space and the most suitable compensator design for a given dynamic specification.

[1]  S. B. Leeb,et al.  A digitally controlled amplifier with ripple cancellation , 2003 .

[2]  J.A. Melkebeek,et al.  Small-Signal$z$-Domain Analysis of Digitally Controlled Converters , 2004, IEEE Transactions on Power Electronics.

[3]  Hong Yi,et al.  A Novel Digital Control Method of a Single-Phase Grid-Connected Inverter Based on a Virtual Closed-Loop Circuit and Complex Vector Representation , 2017 .

[4]  O. Garcia,et al.  Digital control for power supply of a transmitter with variable reference , 2006, Twenty-First Annual IEEE Applied Power Electronics Conference and Exposition, 2006. APEC '06..

[5]  Seth R. Sanders,et al.  Quantization resolution and limit cycling in digitally controlled PWM converters , 2003 .

[6]  P. Zumel,et al.  Efficient CAD tool for power electronics compensator design , 2010, 2010 IEEE Energy Conversion Congress and Exposition.

[7]  S. Saggini,et al.  Simplified Model Reference-Based Autotuningfor Digitally Controlled SMPS , 2008, IEEE Transactions on Power Electronics.

[8]  Yu-Cheng Lin,et al.  A Novel Loop Gain-Adjusting Application Using LSB Tuning for Digitally Controlled DC–DC Power Converters , 2012, IEEE Transactions on Industrial Electronics.

[9]  Jan Melkebeek,et al.  Small-Signal $z$ -Domain Analysis of Digitally Controlled Converters , 2006 .

[10]  B.H. Cho,et al.  Digital state feedback control and feed-forward compensation for a parallel module DC-DC converter using the pole placement technique , 2008, 2008 Twenty-Third Annual IEEE Applied Power Electronics Conference and Exposition.

[11]  Andres Barrado,et al.  Simple method of direct digital design of compensator for DC-DC converters , 2016, 2016 IEEE 17th Workshop on Control and Modeling for Power Electronics (COMPEL).

[12]  H. Venable,et al.  THE K FACTOR : A NEW MATHEMATICAL TOOL FOR STABILITY ANALYSIS AND SYNTHESIS , 2022 .

[13]  A Costabeber,et al.  Digital Time-Optimal Phase Shedding in Multiphase Buck Converters , 2010, IEEE Transactions on Power Electronics.

[14]  S. Saggini,et al.  Autotuning of Digitally Controlled DC–DC Converters Based on Relay Feedback , 2007, IEEE Transactions on Power Electronics.

[15]  D. Maksimovic,et al.  Automated Digital Controller Design for Switching Converters , 2005, 2005 IEEE 36th Power Electronics Specialists Conference.

[16]  D. Maksimovic,et al.  Integration of Frequency Response Measurement Capabilities in Digital Controllers for DC–DC Converters , 2008, IEEE Transactions on Power Electronics.

[17]  Paolo Mattavelli,et al.  Digital control of high-frequency switched-mode power converters , 2015 .

[18]  Dragan Maksimovic,et al.  Specifications-driven design space boundaries for Point-of-Load converters , 2011, 2011 Twenty-Sixth Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[19]  Manuel A Duarte-Mermoud,et al.  Performance index for quality response of dynamical systems. , 2004, ISA transactions.

[20]  Sang-Hyuk Park,et al.  A Wide Input Range Buck-Boost DC–DC Converter Using Hysteresis Triple-Mode Control Technique with Peak Efficiency of 94.8% for RF Energy Harvesting Applications , 2018, Energies.

[21]  S. Saggini,et al.  Digital Autotuning of DC–DC Converters Based on a Model Reference Impulse Response , 2011, IEEE Transactions on Power Electronics.

[22]  D. Maksimovic,et al.  Small-Signal Discrete-Time Modeling of Digitally Controlled PWM Converters , 2007, IEEE Transactions on Power Electronics.

[23]  Jeong-Hwan Yang,et al.  Digital State Feedback Current Control using the Pole Placement Technique , 2007 .

[24]  Keum Cheol Hwang,et al.  Single Inductor-Multiple Output DPWM DC-DC Boost Converter with a High Efficiency and Small Area , 2018 .

[25]  D. Maksimovic,et al.  An Autotuning Digital Controller for DC–DC Power Converters Based on Online Frequency-Response Measurement , 2009, IEEE Transactions on Power Electronics.

[26]  Mor Mordechai Peretz,et al.  Time-Domain Design of Digital Compensators for PWM DC-DC Converters , 2012 .

[27]  I. Batarseh,et al.  Digital controller design for a practicing power electronics engineer , 2007, APEC 07 - Twenty-Second Annual IEEE Applied Power Electronics Conference and Exposition.

[28]  Martin Yeung-Kei Chui,et al.  A programmable integrated digital controller for switching converters with dual-band switching and complex pole-zero compensation , 2005, IEEE Journal of Solid-State Circuits.

[29]  Regan Zane,et al.  The Digital Control Loop , 2015 .

[30]  P. Sathishkumar,et al.  Digital Soft Start Implementation for Minimizing Start Up Transients in High Power DAB-IBDC Converter , 2018 .

[31]  Paolo Mattavelli,et al.  Power Line Communication in Digitally Controlled DC–DC Converters Using Switching Frequency Modulation , 2008, IEEE Transactions on Industrial Electronics.

[32]  Regan Zane,et al.  Discrete-Time Modeling , 2015 .

[33]  Chien-Hung Tsai,et al.  Direct digital compensator design for switching converters , 2010, 2010 International Symposium on Next Generation Electronics.

[34]  P. Zumel,et al.  Design space boundaries of linear compensators applying the k-factor method , 2013, 2013 Twenty-Eighth Annual IEEE Applied Power Electronics Conference and Exposition (APEC).

[35]  Diego G. Lamar,et al.  Efficient Visible Light Communication Transmitters Based on Switching-Mode dc-dc Converters , 2018, Sensors.