The Experts below are selected from a list of 174 Experts worldwide ranked by ideXlab platform
Philip T Krein - One of the best experts on this subject based on the ideXlab platform.
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Ripple Correlation Control with capacitive compensation for photovoltaic applications
Workshop on Control and Modeling for Power Electronics, 2018Co-Authors: Jason Galtieri, Philip T KreinAbstract:A Ripple Correlation Control (RCC) algorithm with capacitive compensation is introduced for photovoltaic applications. In principle, RCC convergence times and steady-state error are reduced with higher switching frequencies, but circuit parasitics have typically limited RCC operation to tens of kHz. With capacitive compensation, phase information is retained at higher frequencies and the practical switching range is extended to 100 kHz. Simulations show that even approximate estimates of parasitic capacitance, with margins of error as high as 20% or so, can greatly extend RCC operating frequency. A 100 kHz boost prototype is constructed and used to verify that phase information is recovered with capacitive compensation.
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Ripple Correlation Control an extremum seeking Control perspective for real time optimization
IEEE Transactions on Power Electronics, 2014Co-Authors: Ali M Bazzi, Philip T KreinAbstract:This paper links the theory of Ripple Correlation Control (RCC) and extremum seeking Control (ESC) with emphasis on application in a solar photovoltaic (PV) system. ESC has been well-established in the automatic Control literature to find the extremum of an objective function. The RCC theory and applications have been developed in the power electronics literature for real-time optimization. Both ESC and RCC are reviewed and discussed. RCC is formulated in a similar approach to ESC, but distinct based on the source of perturbations-mainly external perturbations with ESC and inherent Ripple with RCC. While some recent ESC implementations utilize inherent perturbations, RCC uses high-frequency perturbations in power electronics systems not currently utilized by ESC. The formulation and equivalencies presented here are intended for future research in both methods which can benefit from existing research for further development in theory and applications. Shared aspects that include stability and convergence characteristics are discussed. RCC formulation from an ESC perspective is then applied for maximum power point tracking of a solar PV panel, using high-frequency inherent Ripple in power electronics. This RCC formulation is confirmed to have high tracking effectiveness and fast convergence.
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concerning maximum power point tracking for photovoltaic optimization using Ripple based extremum seeking Control
IEEE Transactions on Power Electronics, 2011Co-Authors: Ali M Bazzi, Philip T KreinAbstract:This paper highlights key contributions in extremum seeking (ES) Control and Ripple Correlation Control (RCC). Maximum power point tracking (MPPT) utilizing the 120-Hz inherent inverter Ripple is shown to be developed in the early 1980s. Even though that specific MPPT development did not explicitly mention ES Control, the analysis presented there shows otherwise. RCC stability and operating properties are also addressed where the fundamental difference between RCC and popular ES Control methods is the perturbation source. Since RCC utilizes inherent switching Ripple in power electronics, the high Ripple frequency leads to fast RCC convergence.
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a comparative study of an exponential adaptive perturb and observe algorithm and Ripple Correlation Control for real time optimization
Workshop on Control and Modeling for Power Electronics, 2010Co-Authors: Veysel T Buyukdegirmenci, Ali M Bazzi, Philip T KreinAbstract:This paper proposes an exponential adaptive perturb and observe algorithm (EAPO) for real-time optimization of dynamic systems. Other adaptive methods are reviewed, and the mathematical formulation of the proposed EAPO is presented. Convergence and stability are discussed. Design requirements for applying EAPO are also addressed in an example for impedance matching. The proposed EAPO is compared to two prior realtime optimization techniques: conventional perturb and observe algorithm (P&O), and Ripple Correlation Control (RCC). The method is shown to track the optimum with lower amplitude oscillations than P&O in the context of maximum power point tracking (MPPT) of a photovoltaic array. It is also compared to RCC in several applications including MPPT, impedance matching, and loss minimization of a separately-excited dc machine. Simulations and experiments show that the proposed EAPO achieves maximum power transfer with less than 4% error. Over all, the steady-state error and tracking response of the proposed EAPO are shown to be similar to RCC.
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Ripple Correlation Control applied to electric vehicle regenerative braking
Power and Energy Conference at Illinois, 2010Co-Authors: Sanghun Choi, Ali M Bazzi, Philip T KreinAbstract:This paper introduces output power maximization of a regenerative braking system using Ripple Correlation Control (RCC). The proposed RCC application thus leads to a reduction in the size of the battery pack in an electric vehicle. Results show that the proposed optimization can increase regenerated power by up to 20% compared to conventional regenerative braking systems. Time and frequency domain simulations in MATLAB/Simulink verify the feasibility of such an application and show promising results in energy savings.
Ali M Bazzi - One of the best experts on this subject based on the ideXlab platform.
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adaptive Ripple Correlation Control arcc for solar maximum power point tracking
Power and Energy Conference at Illinois, 2020Co-Authors: Hasan Abed Al Kader Hammoud, Ali M BazziAbstract:This paper presents a new approach for maximum power point tracking, namely, adaptive Ripple Correlation Control (ARCC). Finding the proper value of the Control law gain for traditional Ripple Correlation Control (RCC) is not straightforward and does not adapt to significant changes in the solar irradiance and temperature. This paper presents a fast and robust method that adapts the Control law gain k in order to achieve maximum power point tracking with small power Ripple content p. The paper starts with a review of the basic concepts of Ripple Correlation Control. We then propose an adaptation technique with three variants: Two fixed gain values, one fixed gain value and another dynamic value, and two dynamic gain values. Afterwards we present simulation results that validate the quick and robust response of our proposed methods compared to P&O and INCO. Next, a comparison to traditional RCC and a comparison between Control gain of various methods are presented. Finally, we conclude by presenting tips on setting up the fixed and varying gain values.
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model based mppt with corrective Ripple Correlation Control
Power and Energy Conference at Illinois, 2020Co-Authors: Hasan Abed Al Kader Hammoud, Ali M BazziAbstract:This paper presents a novel method for obtaining the Control gain for the integral Control law of Ripple Correlation Control (RCC) for Maximum Power Point Tracking. The Control gain in the standard RCC is not straightforward to obtain and does not adapt to significant changes in irradiance and temperature. Our proposed method is based on estimating the maximum power point (MPP) value for a given solar panel model as a function of irradiance and temperature. We then uses a PID Controller to set the Control gain such that MPP is attained. The paper starts with a review of basic concepts of Ripple Correlation Control. Next, we present a curve fitting approach for estimating the maximum power point. The set point is then used along with the measured value of power to obtain an error signal for the PID which generates our adaptive/corrective Control gain k. We then present simulation results for several irradiance settings. A sensitivity analysis and an analysis on the number of points required for the MPP fit are then presented. Finally we compare the proposed model based RCC to the traditional RCC.
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Ripple Correlation Control an extremum seeking Control perspective for real time optimization
IEEE Transactions on Power Electronics, 2014Co-Authors: Ali M Bazzi, Philip T KreinAbstract:This paper links the theory of Ripple Correlation Control (RCC) and extremum seeking Control (ESC) with emphasis on application in a solar photovoltaic (PV) system. ESC has been well-established in the automatic Control literature to find the extremum of an objective function. The RCC theory and applications have been developed in the power electronics literature for real-time optimization. Both ESC and RCC are reviewed and discussed. RCC is formulated in a similar approach to ESC, but distinct based on the source of perturbations-mainly external perturbations with ESC and inherent Ripple with RCC. While some recent ESC implementations utilize inherent perturbations, RCC uses high-frequency perturbations in power electronics systems not currently utilized by ESC. The formulation and equivalencies presented here are intended for future research in both methods which can benefit from existing research for further development in theory and applications. Shared aspects that include stability and convergence characteristics are discussed. RCC formulation from an ESC perspective is then applied for maximum power point tracking of a solar PV panel, using high-frequency inherent Ripple in power electronics. This RCC formulation is confirmed to have high tracking effectiveness and fast convergence.
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concerning maximum power point tracking for photovoltaic optimization using Ripple based extremum seeking Control
IEEE Transactions on Power Electronics, 2011Co-Authors: Ali M Bazzi, Philip T KreinAbstract:This paper highlights key contributions in extremum seeking (ES) Control and Ripple Correlation Control (RCC). Maximum power point tracking (MPPT) utilizing the 120-Hz inherent inverter Ripple is shown to be developed in the early 1980s. Even though that specific MPPT development did not explicitly mention ES Control, the analysis presented there shows otherwise. RCC stability and operating properties are also addressed where the fundamental difference between RCC and popular ES Control methods is the perturbation source. Since RCC utilizes inherent switching Ripple in power electronics, the high Ripple frequency leads to fast RCC convergence.
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a comparative study of an exponential adaptive perturb and observe algorithm and Ripple Correlation Control for real time optimization
Workshop on Control and Modeling for Power Electronics, 2010Co-Authors: Veysel T Buyukdegirmenci, Ali M Bazzi, Philip T KreinAbstract:This paper proposes an exponential adaptive perturb and observe algorithm (EAPO) for real-time optimization of dynamic systems. Other adaptive methods are reviewed, and the mathematical formulation of the proposed EAPO is presented. Convergence and stability are discussed. Design requirements for applying EAPO are also addressed in an example for impedance matching. The proposed EAPO is compared to two prior realtime optimization techniques: conventional perturb and observe algorithm (P&O), and Ripple Correlation Control (RCC). The method is shown to track the optimum with lower amplitude oscillations than P&O in the context of maximum power point tracking (MPPT) of a photovoltaic array. It is also compared to RCC in several applications including MPPT, impedance matching, and loss minimization of a separately-excited dc machine. Simulations and experiments show that the proposed EAPO achieves maximum power transfer with less than 4% error. Over all, the steady-state error and tracking response of the proposed EAPO are shown to be similar to RCC.
Gabriele Grandi - One of the best experts on this subject based on the ideXlab platform.
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Ripple Correlation Control mppt scheme applied to a three phase flying capacitor pv system
2020Co-Authors: Mattia Ricco, Manel Hammami, Riccardo Mandrioli, Gabriele GrandiAbstract:This chapter introduces a Ripple Correlation Control (RCC) algorithm for tracking the maximum power point (MPP) for a flying capacitor three-level three-phase photovoltaic (PV) system. Although RCC maximum power point tracking (MPPT) method has been widely used on single-phase plants, a three-phase implementation based on sinusoidal carrier PWM has not been presented yet. The inherent oscillations of the PV current and voltage are employed as a perturbation for the RCC MPPT system. The proposed algorithm adopts the PV current and voltage 3rd harmonic component for estimating the power (or current) derivative, dPpv/dVpv (or dIpv/dVpv). Firstly, referring to the carrier-based sinusoidal pulse width modulation (SPWM), the flying capacitor inverter modulation scheme is presented. Secondly, the proposed RCC MPPT method is introduced. Finally, multiple MATLAB-/Simulink-based simulations of the RCC MPPT algorithm acting on a grid-connected PV system are provided. Both steady-state and dynamic (irradiance increase and decrease) conditions present good performances.
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three phase three level flying capacitor pv generation system with an embedded Ripple Correlation Control mppt algorithm
Electronics, 2019Co-Authors: Manel Hammami, Mattia Ricco, Alex Ruderman, Gabriele GrandiAbstract:This paper presents the implementation of a maximum power point tracking (MPPT) algorithm in a multilevel three-phase photovoltaic (PV) system using the Ripple Correlation Control (RCC) method. Basically, RCC adopts the inherent oscillations of PV current and voltage as perturbation, and it has been predominantly used for single-phase configurations, where the oscillations correspond to the 2nd order harmonics. The implementation of an RCC-MPPT algorithm in a three-phase system has not been presented yet in the literature. In this paper, the considered three-phase three-level converter is a three-level flying capacitor (FC) inverter. The proffered RCC method uses the 3rd harmonic components of PV current and voltage for the estimation of the voltage derivative of the power dPpv/dVpv (or current, dIpv/dVpv), compelling the PV array to operate at or very close to the maximum power point. The analysis and calculation of the low-frequency PV current and voltage Ripple harmonic components in the three-phase flying capacitor inverter is presented first, with reference to centered carrier-based three-level PWM. The whole grid-connected PV generation scheme has been implemented by MATLAB/Simulink, and detailed numerical simulations verified the effectiveness of the Control method in both steady-state and dynamic conditions, emulating different sun irradiance transients.
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a single phase multilevel pv generation system with an improved Ripple Correlation Control mppt algorithm
Energies, 2017Co-Authors: Manel Hammami, Gabriele GrandiAbstract:The implementation of maximum power point tracking (MPPT) schemes by the Ripple Correlation Control (RCC) algorithm is presented in this paper. A reference is made to single-phase single-stage multilevel photovoltaic (PV) generation systems, when the inverter input variables (PV voltage and PV current) have multiple low-frequency (Ripple) harmonics. The harmonic analysis is carried out with reference to a multilevel configuration consisting of an H-bridge inverter and level doubling network (LDN) cell, leading to the multilevel inverter having double the output voltage levels as compared to the basic H-bridge inverter topology (i.e., five levels vs. three levels). The LDN cell is basically a half-bridge fed by a floating capacitor, with self-balancing voltage capability. The multilevel configuration introduces additional PV voltage and current low-frequency harmonics, perturbing the basic implementation of the RCC scheme (based on the second harmonic component), leading to malfunctioning. The proposed RCC algorithm employs the PV current and voltage harmonics at a specific frequency for the estimation of the voltage derivative of power dP/dV (or dI/dV), driving the PV operating point toward the maximum power point (MPP) in a faster and more precise manner. The steady-state and transient performances of the proposed RCC-MPPT schemes have been preliminarily tested and compared using MATLAB/Simulink. Results have been verified by experimental tests considering the whole multilevel PV generation system, including real PV modules, multilevel insulated-gate bipolar transistor (IGBT) inverters, and utility grids.
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single phase single stage photovoltaic generation system based on a Ripple Correlation Control maximum power point tracking
IEEE Transactions on Energy Conversion, 2006Co-Authors: D Casadei, Gabriele Grandi, C RossiAbstract:A maximum power point tracking algorithm for single-stage converters connecting photovoltaic (PV) panels to a single-phase grid is presented in this paper. The algorithm is based on the application of the "Ripple Correlation Control" using as perturbation signals the current and voltage low-frequency oscillations introduced in the PV panels by the single-phase utility grid. The proposed Control technique allows the generation of sinusoidal grid currents with unity power factor. The algorithm has been developed to allow an array of PV modules to be connected to the grid by using a single-stage converter. This simple structure yields higher efficiency and reliability when compared with standard solutions based on double-stage converter configurations. The proposed maximum power point tracking algorithm has been numerically simulated and experimentally verified by means of a converter prototype connected to a single-phase grid. The results are presented in the paper, showing the effectiveness of the proposed system.
P T Krein - One of the best experts on this subject based on the ideXlab platform.
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input power minimization of an induction motor operating from an electronic drive under Ripple Correlation Control
Power Electronics Specialists Conference, 2008Co-Authors: Ali M Bazzi, P T KreinAbstract:This paper elaborates on the application of Ripple Correlation Control (RCC) to induction motor input power minimization. Simulations, hardware experiments, and frequency analyses verify that the direct component of the rotor flux in the synchronous frame (lambdae dr) can be adjusted to minimize the input power to the motor while maintaining the required output power. Motor characteristics are shown to give a convex input power function with respect to lambdae dr which could be feasible for optimization using RCC. Sensitivity analyses based on RCC of a boost converter and for an induction motor are presented. A Simulinkreg simulation shows the convergence of the Ripple Correlation Controller to the optimum operating point that was determined by hardware experiments. Other results include the use of flux estimators from stator-side voltage and current measurements. Efficiency improvement has been verified across the load torque range, including light load conditions.
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digital Ripple Correlation Control for photovoltaic applications
Power Electronics Specialists Conference, 2007Co-Authors: Jonathan W Kimball, P T KreinAbstract:Ripple Correlation Control (RCC) is a fast, robust online optimization technique. RCC is particularly suited for switching power converters, where the inherent Ripple provides information about the system operating point. The present work examines a digital formulation that has reduced power consumption and greater robustness. A maximum power point tracker for a photovoltaic panel demonstrates greater than 99% tracking accuracy and fast convergence.
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dynamic maximum power point tracking of photovoltaic arrays using Ripple Correlation Control
IEEE Transactions on Power Electronics, 2006Co-Authors: Trishan Esram, Jonathan W Kimball, P.l. Chapman, P T Krein, Pallab MidyaAbstract:A dynamically rapid method used for tracking the maximum power point of photovoltaic arrays, known as Ripple Correlation Control, is presented and verified against experiment. The technique takes advantage of the signal Ripple, which is automatically present in power converters. The Ripple is interpreted as a perturbation from which a gradient ascent optimization can be realized. The technique converges asymptotically at maximum speed to the maximum power point without the benefit of any array parameters or measurements. The technique has simple circuit implementations
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Fundamental aspects of Ripple Correlation Control of electric machinery
IEEE 34th Annual Conference on Power Electronics Specialist 2003. PESC '03., 2003Co-Authors: J.r. Wells, P.l. Chapman, P T KreinAbstract:Ripple Correlation Control (RCC) has been established as a cost function minimization strategy for problems ranging from source impedance matching to static VAR compensators and more recently to electric machinery. The dynamics of machines often makes direct application of RCC not possible or not practical. This paper addresses the fundamental challenges associated with implementation of RCC optimization in electric machinery. Specifically, the paper presents a steady state error analysis of several practical RCC Control laws, develops a systematic approach to observer design to cast the optimization of a dynamic process into a static framework, and presents the benefits of an alternative RCC Control law for use in electric machinery Controllers.
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observer based techniques in Ripple Correlation Control applied to power electronic systems
Power Electronics Specialists Conference, 2001Co-Authors: D L Logue, P T KreinAbstract:Ripple Correlation Control is a general optimization method for use with power electronic interfaced systems. The method relies on gradient information extracted from the Ripple associated with these systems. The variable to be optimized and the variable that the optimization is being performed with respect to, must both be available to the Controller. This paper discusses ways of dealing with the difficulties that arise when these signals cannot be measured due to dynamics within the system.
Jonathan W Kimball - One of the best experts on this subject based on the ideXlab platform.
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discrete time Ripple Correlation Control for maximum power point tracking
IEEE Transactions on Power Electronics, 2008Co-Authors: Jonathan W Kimball, Philip T KreinAbstract:Ripple Correlation Control (RCC) is a high-performance real-time optimization technique that has been applied to photovoltaic maximum power point tracking. This paper extends the previous analog technique to the digital domain. The proposed digital implementation is less expensive, more flexible, and more robust. With a few simplifications, the RCC method is reduced to a sampling problem; that is, if the appropriate variables are sampled at the correct times, the discrete-time RCC (DRCC) algorithm can quickly find the optimal operating point. First, the general DRCC method is derived and stability is proven. Then, DRCC is applied to the photovoltaic maximum power point tracking problem. Experimental results verify tracking accuracy greater than 98% with an update rate greater than 1 kHz.
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digital Ripple Correlation Control for photovoltaic applications
Power Electronics Specialists Conference, 2007Co-Authors: Jonathan W Kimball, P T KreinAbstract:Ripple Correlation Control (RCC) is a fast, robust online optimization technique. RCC is particularly suited for switching power converters, where the inherent Ripple provides information about the system operating point. The present work examines a digital formulation that has reduced power consumption and greater robustness. A maximum power point tracker for a photovoltaic panel demonstrates greater than 99% tracking accuracy and fast convergence.
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dynamic maximum power point tracking of photovoltaic arrays using Ripple Correlation Control
IEEE Transactions on Power Electronics, 2006Co-Authors: Trishan Esram, Jonathan W Kimball, P.l. Chapman, P T Krein, Pallab MidyaAbstract:A dynamically rapid method used for tracking the maximum power point of photovoltaic arrays, known as Ripple Correlation Control, is presented and verified against experiment. The technique takes advantage of the signal Ripple, which is automatically present in power converters. The Ripple is interpreted as a perturbation from which a gradient ascent optimization can be realized. The technique converges asymptotically at maximum speed to the maximum power point without the benefit of any array parameters or measurements. The technique has simple circuit implementations
