Polynomial Curve Slope Compensation for Peak-Current-Mode-Controlled Power Converters

Linear ramp slope compensation (LRC) and quadratic slope compensation (QSC) are commonly implemented in peak-current-mode-controlled dc-dc converters in order to minimize subharmonic and chaotic oscillations. Both compensating schemes rely on the linearized state-space averaged model (LSSA) of the converter. The LSSA ignores the impact that switching actions have on the stability of converters. In order to include switching events, the nonlinear analysis method based on the Monodromy matrix was introduced to describe a complete-cycle stability. Analyses on analog-controlled dc-dc converters applying this method show that system stability is strongly dependent on the change of the derivative of the slope at the time of switching instant. However, in a mixed-signal-controlled system, the digitalization effect contributes differently to system stability. This paper shows a full complete-cycle stability analysis using this nonlinear analysis method, which is applied to a mixed-signal-controlled converter. Through this analysis, a generalized equation is derived that reveals for the first time the real boundary stability limits for LRC and QSC. Furthermore, this generalized equation allows the design of a new compensating scheme, which is able to increase system stability. The proposed scheme is called polynomial curve slope compensation (PCSC) and it is demonstrated that PCSC increases the stable margin by 30% compared to LRC and 20% to QSC. This outcome is proved experimentally by using an interleaved dc-dc converter that is built for this work

Stability Study and Nonlinear Analysis of DC-DC Power Converters with Constant Power Loads at the Fast Timescale

Rapidly growing distributed renewable networks make an increasing demand on various types of power converters to feed different loads. Power converters with constant power load are one typical configuration that can degrade the stability of the power conversion system due to the negative impedance characteristic. This paper presents a nonlinear analysis method using the developed complete-cycle solution matrix method by transforming the original linear time-variant system into a summation of segmented linear time-invariant systems. Thus, the stability of the nonlinear system can be studied using a series of the corresponding state transition matrix and saltation matrix. As this derived matrix contains all the comprehensive information relating to the system’s stability, the influence of the constant power load to system’s fast-timescale stability in both continuous conduction mode and the discontinuous conduction mode can be fully investigated and analyzed. The phenomena of fast-timescale instability around switching frequency for power converters with a constant power load are observed and investigated numerically. Finally, experimental results have proven the analysis and verified the effectiveness of the developed method

DC-Transformer Modelling, Analysis and Comparison of the Experimental Investigation of a Non-Inverting and Non-Isolated Nx Multilevel Boost Converter (Nx MBC) for Low to High DC Voltage Applications

This paper mainly focuses on the analysis, DC-transformer modeling, comparison, and experimental investigation of a non-inverting and non-isolated Nx multilevel boost converter (Nx MBC) for low to high DC applications. Recently, numerous isolated and non-isolated DC-DC converter configurations have been addressed for low to high DC voltage conversion purposes, which is vital for several applications (e.g., renewable energy, medical equipment, hybrid vehicles, fuel cells, DC-links, multilevel inverters, and drive applications), by utilizing and modifying the structure of reactive elements (switched capacitors and switched inductor circuitry). Among all the switched reactive structures, voltage multiplier circuitry provides a feasible solution for low to high DC voltage conversion due to its flexible and modular structure, voltage clamping capability, reduced rating of components, and ease of modification. Non-inverting and non-isolated Nx MBC combine the features and structures of conventional boost converters and voltage multiplier circuitry. DC-transformer modeling of Nx MBC is discussed for the continuous current mode (CCM) and discontinuous current mode (DCM), which helps to analyze the characteristics of the converter in a more practical way and helps to study the effect of semiconductor components, internal resistances, and load on the voltage conversion ratio of the converter. The mode of operation of Nx MBC in the CCM and DCM is also discussed with the boundary condition. The derived analysis is verified by simulations and experimental investigations, and the obtained results of 3x MBC always show good agreement with each other and the theoretical analysis

One-Cycle Zero-Integral-Error Current Control for Shunt Active Power Filters

[EN] Current control has, for decades, been one of the more challenging research fields in the development of power converters. Simple and robust nonlinear methods like hysteresis or sigma-delta controllers have been commonly used, while sophisticated linear controllers based on classical control theory have been developed for PWM-based converters. The one-cycle current control technique is a nonlinear technique based on cycle-by-cycle calculation of the ON time of the converter switches for the next switching period. This kind of controller requires accurate measurement of voltages and currents in order achieve a precise current tracking. These techniques have been frequently used in the control of power converters generating low-frequency currents, where the reference varies slowly compared with the switching frequency. Its application is not so common in active power filter current controllers due to the fast variation of the references that demands not only accurate measurements but also high-speed computing. This paper proposes a novel one-cycle digital current controller based on the minimization of the integral error of the current. Its application in a three-leg four-wire shunt active power filter is presented, including a stability analysis considering the switching pattern selection. Furthermore, simulated and experimental results are presented to validate the proposed controller.Orts-Grau, S.; Balaguer-Herrero, P.; Alfonso-Gil, JC.; Martínez-Márquez, CI.; Gimeno Sales, FJ.; Segui-Chilet, S. (2020). One-Cycle Zero-Integral-Error Current Control for Shunt Active Power Filters. Electronics. 9(12):1-16. https://doi.org/10.3390/electronics9122008S116912Orts-Grau, S., Gimeno-Sales, F. J., Abellan-Garcia, A., Segui-Chilet, S., & Alfonso-Gil, J. C. (2010). Improved Shunt Active Power Compensator for IEEE Standard 1459 Compliance. IEEE Transactions on Power Delivery, 25(4), 2692-2701. doi:10.1109/tpwrd.2010.2049033Orts-Grau, S., Gimeno-Sales, F. J., Segui-Chilet, S., Abellan-Garcia, A., Alcaniz-Fillol, M., & Masot-Peris, R. (2009). Selective Compensation in Four-Wire Electric Systems Based on a New Equivalent Conductance Approach. IEEE Transactions on Industrial Electronics, 56(8), 2862-2874. doi:10.1109/tie.2009.2014368Trinh, Q.-N., & Lee, H.-H. (2013). An Advanced Current Control Strategy for Three-Phase Shunt Active Power Filters. IEEE Transactions on Industrial Electronics, 60(12), 5400-5410. doi:10.1109/tie.2012.2229677Bosch, S., Staiger, J., & Steinhart, H. (2018). Predictive Current Control for an Active Power Filter With LCL-Filter. IEEE Transactions on Industrial Electronics, 65(6), 4943-4952. doi:10.1109/tie.2017.2772176Balasubramanian, R., Parkavikathirvelu, K., Sankaran, R., & Amirtharajan, R. (2019). Design, Simulation and Hardware Implementation of Shunt Hybrid Compensator Using Synchronous Rotating Reference Frame (SRRF)-Based Control Technique. Electronics, 8(1), 42. doi:10.3390/electronics8010042Imam, A. A., Sreerama Kumar, R., & Al-Turki, Y. A. (2020). Modeling and Simulation of a PI Controlled Shunt Active Power Filter for Power Quality Enhancement Based on P-Q Theory. Electronics, 9(4), 637. doi:10.3390/electronics9040637Panigrahi, R., Subudhi, B., & Panda, P. C. (2016). A Robust LQG Servo Control Strategy of Shunt-Active Power Filter for Power Quality Enhancement. IEEE Transactions on Power Electronics, 31(4), 2860-2869. doi:10.1109/tpel.2015.2456155Herman, L., Papic, I., & Blazic, B. (2014). A Proportional-Resonant Current Controller for Selective Harmonic Compensation in a Hybrid Active Power Filter. IEEE Transactions on Power Delivery, 29(5), 2055-2065. doi:10.1109/tpwrd.2014.2344770Panigrahi, R., & Subudhi, B. (2017). Performance Enhancement of Shunt Active Power Filter Using a Kalman Filter-Based ${{{\rm H}}_\infty }$ Control Strategy. IEEE Transactions on Power Electronics, 32(4), 2622-2630. doi:10.1109/tpel.2016.2572142Jiang, W., Ding, X., Ni, Y., Wang, J., Wang, L., & Ma, W. (2018). An Improved Deadbeat Control for a Three-Phase Three-Line Active Power Filter With Current-Tracking Error Compensation. IEEE Transactions on Power Electronics, 33(3), 2061-2072. doi:10.1109/tpel.2017.2693325Buso, S., Caldognetto, T., & Brandao, D. (2015). Dead-Beat Current Controller for Voltage Source Converters with Improved Large Signal Response. IEEE Transactions on Industry Applications, 1-1. doi:10.1109/tia.2015.2488644Tarisciotti, L., Formentini, A., Gaeta, A., Degano, M., Zanchetta, P., Rabbeni, R., & Pucci, M. (2017). Model Predictive Control for Shunt Active Filters With Fixed Switching Frequency. IEEE Transactions on Industry Applications, 53(1), 296-304. doi:10.1109/tia.2016.2606364Kumar, M., & Gupta, R. (2017). Sampled-Time-Domain Analysis of a Digitally Implemented Current Controlled Inverter. IEEE Transactions on Industrial Electronics, 64(1), 217-227. doi:10.1109/tie.2016.2609840Ho, C. N.-M., Cheung, V. S. P., & Chung, H. S.-H. (2009). Constant-Frequency Hysteresis Current Control of Grid-Connected VSI Without Bandwidth Control. IEEE Transactions on Power Electronics, 24(11), 2484-2495. doi:10.1109/tpel.2009.2031804Wu, F., Feng, F., Luo, L., Duan, J., & Sun, L. (2015). Sampling period online adjusting-based hysteresis current control without band with constant switching frequency. IEEE Transactions on Industrial Electronics, 62(1), 270-277. doi:10.1109/tie.2014.2326992Holmes, D. G., Davoodnezhad, R., & McGrath, B. P. (2013). An Improved Three-Phase Variable-Band Hysteresis Current Regulator. IEEE Transactions on Power Electronics, 28(1), 441-450. doi:10.1109/tpel.2012.2199133Komurcugil, H., Bayhan, S., & Abu-Rub, H. (2017). Variable- and Fixed-Switching-Frequency-Based HCC Methods for Grid-Connected VSI With Active Damping and Zero Steady-State Error. IEEE Transactions on Industrial Electronics, 64(9), 7009-7018. doi:10.1109/tie.2017.2686331Chang, C.-H., Wu, F.-Y., & Chen, Y.-M. (2012). Modularized Bidirectional Grid-Connected Inverter With Constant-Frequency Asynchronous Sigma–Delta Modulation. IEEE Transactions on Industrial Electronics, 59(11), 4088-4100. doi:10.1109/tie.2011.2176693Mertens, A. (1994). Performance analysis of three-phase inverters controlled by synchronous delta-modulation systems. IEEE Transactions on Industry Applications, 30(4), 1016-1027. doi:10.1109/28.297919Morales, J., de Vicuna, L. G., Guzman, R., Castilla, M., & Miret, J. (2018). Modeling and Sliding Mode Control for Three-Phase Active Power Filters Using the Vector Operation Technique. IEEE Transactions on Industrial Electronics, 65(9), 6828-6838. doi:10.1109/tie.2018.2795528Guzman, R., de Vicuna, L. G., Morales, J., Castilla, M., & Miret, J. (2016). Model-Based Control for a Three-Phase Shunt Active Power Filter. IEEE Transactions on Industrial Electronics, 63(7), 3998-4007. doi:10.1109/tie.2016.2540580Pichan, M., & Rastegar, H. (2017). Sliding-Mode Control of Four-Leg Inverter With Fixed Switching Frequency for Uninterruptible Power Supply Applications. IEEE Transactions on Industrial Electronics, 64(8), 6805-6814. doi:10.1109/tie.2017.2686346E. S., S., E. K., P., Chatterjee, K., & Bandyopadhyay, S. (2014). An Active Harmonic Filter Based on One-Cycle Control. IEEE Transactions on Industrial Electronics, 61(8), 3799-3809. doi:10.1109/tie.2013.2286558Wang, L., Han, X., Ren, C., Yang, Y., & Wang, P. (2018). A Modified One-Cycle-Control-Based Active Power Filter for Harmonic Compensation. IEEE Transactions on Industrial Electronics, 65(1), 738-748. doi:10.1109/tie.2017.2682021Jin, T., & Smedley, K. M. (2006). Operation of One-Cycle Controlled Three-Phase Active Power Filter With Unbalanced Source and Load. IEEE Transactions on Power Electronics, 21(5), 1403-1412. doi:10.1109/tpel.2006.880264Hirve, S., Chatterjee, K., Fernandes, B. G., Imayavaramban, M., & Dwari, S. (2007). PLL-Less Active Power Filter Based on One-Cycle Control for Compensating Unbalanced Loads in Three-Phase Four-Wire System. IEEE Transactions on Power Delivery, 22(4), 2457-2465. doi:10.1109/tpwrd.2007.893450Qiao, C., Smedley, K. M., & Maddaleno, F. (2004). A Single-Phase Active Power Filter With One-Cycle Control Under Unipolar Operation. IEEE Transactions on Circuits and Systems I: Regular Papers, 51(8), 1623-1630. doi:10.1109/tcsi.2004.832801Qiao, C., Jin, T., & MaSmedley, K. (2004). One-Cycle Control of Three-Phase Active Power Filter With Vector Operation. IEEE Transactions on Industrial Electronics, 51(2), 455-463. doi:10.1109/tie.2004.82522

Modeling and Analysis of Power Processing Systems (MAPPS). Volume 1: Technical report

Computer aided design and analysis techniques were applied to power processing equipment. Topics covered include: (1) discrete time domain analysis of switching regulators for performance analysis; (2) design optimization of power converters using augmented Lagrangian penalty function technique; (3) investigation of current-injected multiloop controlled switching regulators; and (4) application of optimization for Navy VSTOL energy power system. The generation of the mathematical models and the development and application of computer aided design techniques to solve the different mathematical models are discussed. Recommendations are made for future work that would enhance the application of the computer aided design techniques for power processing systems

Advances in Control of Power Electronic Converters

This book proposes a list of contributions in the field of control of power electronics converters for different topologies: DC-DC, DC-AC and AC-DC. It particularly focuses on the use of different advanced control techniques with the aim of improving the performances, flexibility and efficiency in the context of several operation conditions. Sliding mode control, fuzzy logic based control, dead time compensation and optimal linear control are among the techniques developed in the special issue. Simulation and experimental results are provided by the authors to validate the proposed control strategies

Design of an Integrated Silicon Carbide Nonlinear-carrier PWM Controller for Boost Converter Applications

Power electronics consisting of a switch mode power supply with feedback control have a great number of applications, including many that require extreme environment capability, such as the aerospace and automotive industries. Silicon carbide (SiC) is a common material in which power devices are created for use in switch mode power supplies, such as boost converters, giving those power supplies extremely high temperature capabilities. To truly realize the temperature capabilities of SiC in power supplies, an integrated SiC converter has been designed that is also high-temperature capable. Herein, the properties of SiC integrate circuit (IC) processes are discussed and nonlinear-carrier (NLC) control is proposed as a controller topology that can work within the design challenges presented by SiC. A boost converter with an NLC controller is demonstrated in simulation with circuit blocks built entirely from SiC IC models

Hybrid AC-High Voltage DC Grid Stability and Controls

abstract: The growth of energy demands in recent years has been increasing faster than the expansion of transmission facility construction. This tendency cooperating with the continuous investing on the renewable energy resources drives the research, development, and construction of HVDC projects to create a more reliable, affordable, and environmentally friendly power grid. Constructing the hybrid AC-HVDC grid is a significant move in the development of the HVDC techniques; the form of dc system is evolving from the point-to-point stand-alone dc links to the embedded HVDC system and the multi-terminal HVDC (MTDC) system. The MTDC is a solution for the renewable energy interconnections, and the MTDC grids can improve the power system reliability, flexibility in economic dispatches, and converter/cable utilizing efficiencies. The dissertation reviews the HVDC technologies, discusses the stability issues regarding the ac and HVDC connections, proposes a novel power oscillation control strategy to improve system stability, and develops a nonlinear voltage droop control strategy for the MTDC grid. To verify the effectiveness the proposed power oscillation control strategy, a long distance paralleled AC-HVDC transmission test system is employed. Based on the PSCAD/EMTDC platform simulation results, the proposed power oscillation control strategy can improve the system dynamic performance and attenuate the power oscillations effectively. To validate the nonlinear voltage droop control strategy, three droop controls schemes are designed according to the proposed nonlinear voltage droop control design procedures. These control schemes are tested in a hybrid AC-MTDC system. The hybrid AC-MTDC system, which is first proposed in this dissertation, consists of two ac grids, two wind farms and a five-terminal HVDC grid connecting them. Simulation studies are performed in the PSCAD/EMTDC platform. According to the simulation results, all the three design schemes have their unique salient features.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

Small-signal modeling of current-mode controlled modular DC-DC converters using the state-space algebraic approach

Small-signal models are useful tools to preliminary understand the dynamics of interconnected systems like modular dc-dc converters which find a wide range of industrial applications. This work proposes a state-space-based averaged small-signal model in symbolic form for a peak current-mode controlled parallel-input/parallel-output buck converter operating in the continuous-conduction mode. In modeling the converter power-stage each module is independently represented. For modeling the current-mode control the state-space algebraic approach is used to incorporate the current-mode control-law into the power-stage equations. For each module two parasitic elements in addition to the current-loop sampling action are included in the derivation. Furthermore, the control-to-output voltage transfer functions are presented in symbolic form for two cases of interest: the first when the converter has two non-identical modules to study the effect of inductor mismatch, and the second when the converter is composed of n-connected identical modules to assess the effect of varying the number of modules. All responses from PSIM cycle-by-cycle simulations are in good agreement with the mathematical model predictions up to half the switching frequency