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Aleksandar Prodic - One of the best experts on this subject based on the ideXlab platform.

  • hardware efficient auto tuned linear gain based minimum deviation Digital Controller for indirect energy transfer converters
    Applied Power Electronics Conference, 2017
    Co-Authors: Shadi Dashmiz, Aleksandar Prodic, Behzad Mahdavikhah, Brent Mcdonald
    Abstract:

    This paper introduces a robust, hardware-efficient auto-tuned Digital Controller applicable to various hard switching dc-dc converters, including indirect energy transfesr topologies. Unlike existing fast transient Controllers for indirect energy transfer converters, the Controller achieves fast transient response and practically minimum deviation of the output voltage without depending on information about converter parameters, i.e. inductor and output capacitor values. This is achieved by utilizing an auto-tuned non-linear Controller that, based on the load-step information during a transient, finds the switching sequence for the converter to ramp up/down the inductor current to its new steady state average value in a single on/off switching action. Experimental results obtained from a 1.5 V to 3.3 V, 1A, 500 kHz boost prototype verify response with practically minimum output voltage deviation and demonstrate a more than 50% reduction of both output voltage deviation and recovery time compared to a voltage mode, fast PID-based Controller.

  • extended wide load range model for multi level dc dc converters and a practical dual mode Digital Controller
    Applied Power Electronics Conference, 2016
    Co-Authors: Nenad Vukadinovic, Aleksandar Prodic, Brett A Miwa, Cory B Arnold, M W Baker
    Abstract:

    This paper addresses limitations of previous models of multi-level flying capacitor (ML-FC) dc-dc converters, in terms of not being able to predict instability in the regulation of the flying capacitor voltage under non-negligible inductor current ripple conditions, usually existing under light to medium load operating conditions. Assuming small-ripple approximation, linear ac equivalent circuit is derived for a general N-level FC dc-dc buck converter and, through a geometrical analysis, limitations of that model are explained. Also, related stability problems are addressed. Then, an extended mathematical model that takes into account the ripple component of the inductor current is derived and used in the design of a practical dual-mode Digital Controller, which for non-negligible ripple operating conditions changes its mode of operation. Validity of the model and the functionality of the introduced Controller are verified both through simulations and experimental verifications. Performance of this Controller is tested with a wide input ???? ??/?? ??, ?????? kHz, ???? W, three-level experimental prototype.

  • Digitally controlled steered inductor buck converter for improving heavy to light load transient response
    Power Electronics Specialists Conference, 2008
    Co-Authors: Andrija Stupar, Zdravko Lukic, Aleksandar Prodic
    Abstract:

    In this paper a novel Digital Controller and modified buck converter for improving heavy-to-light load transient response of low-power low-voltage dc-dc converters is introduced. The system is primarily designed for point-of-load (PoL) converters providing low regulated voltages for Digital loads. In conventional buck topologies, the low output voltage, often below 1 V, severely limits the inductor current slew rate during the transients. To overcome this physical limitation, a modification is introduced whereby during heavy-to-light transients, the inductor current is, by the means of two extra switches, steered into the source and at the same time, the slew-rate of the current is significantly increased. The steering action is governed by a Digital Controller. The effectiveness of the system is verified on an FPGA-controlled, 12 V to 0.9 V, 10 W, experimental prototype. The results show that the steered-inductor Digitally controlled buck converter has much shorter settling time and provides 2.8 times smaller overshoot than the conventional buck.

  • multibit sigma delta pwm Digital Controller ic for dc dc converters operating at switching frequencies beyond 10 mhz
    IEEE Transactions on Power Electronics, 2007
    Co-Authors: Zdravko Lukic, N Rahman, Aleksandar Prodic
    Abstract:

    An integrated Digital Controller for dc-dc switch-mode power supplies (SMPS) used in portable applications is introduced. The Controller has very low power consumption, fast dynamic response, and can operate at programmable constant switching frequencies exceeding 10 MHz. To achieve these characteristics, three novel functional blocks, a Digital pulse-width modulator based on second-order sigma-delta concept (Sigma-Delta DPWM), dual-clocking mode compensator, and nonlinear analog-to-Digital converter are combined. In steady state, to minimize power consumption, the Controller is clocked at a frequency lower than SMPS switching frequency. During transients the clock rate is increased to the switching frequency improving transient response. The Controller integrated circuit (IC) is fabricated in a standard 0.18-mum process and tested with a 750-mW buck converter prototype. Experimental results show the Controller current consumption of 55 muA/MHz and verify closed-loop operation at programmable switching frequencies up to 12.3 MHz. Simulation results indicating that this architecture can potentially support operation at switching frequencies beyond 100 MHz are also presented.

  • dead zone Digital Controller for improved dynamic response of power factor preregulators
    Applied Power Electronics Conference, 2003
    Co-Authors: Aleksandar Prodic, Dragan Maksimovic, Robert W Erickson
    Abstract:

    This paper presents a simple control method for improvement of dynamic responses in a Digitally controlled low-harmonic rectifier with power factor correction (PFC). The Controller uses a fixed or self-adjusting dead zone in analog-to-Digital conversion to eliminate the output capacitor ripple from the voltage control loop. The proposed control methods are tested in a completely Digitally controlled 200 W boost PFC operating at 200 kHz switching frequency. Experimental results show that the simple Controller implementation results in low current harmonics and significantly improved output voltage transient responses.

Dragan Maksimovic - One of the best experts on this subject based on the ideXlab platform.

  • a Digital current mode control technique for dc dc converters
    Applied Power Electronics Conference, 2005
    Co-Authors: H Peng, Dragan Maksimovic
    Abstract:

    This paper introduces a Digital average current-mode Controller architecture based on a low-resolution current A/D converter and a simple Digital Controller realization. The proposed approach combines advantages of practical Digital realization and current-mode control for DC-DC converters operating at high switching frequencies. An experimental test circuit includes an experimental prototype current A/D converter, a Controller implemented on an FPGA, and a 6 V-to-1.8 V, 10 A synchronous buck power stage operating at 200 KHz. Experimental verification results are described

  • Digital current mode Controller for dc dc converters
    Applied Power Electronics Conference, 2005
    Co-Authors: H Peng, Dragan Maksimovic
    Abstract:

    This paper introduces a Digital average current-mode Controller architecture based on a low-resolution current A/D converter and a simple Digital Controller realization. The proposed approach combines advantages of practical Digital realization and current-mode control for DC-DC converters operating at high switching frequencies. An experimental test circuit includes an experimental prototype current A/D converter, a Controller implemented on an FPGA, and a 6 V-to-1.8 V, 10 A synchronous buck power stage operating at 200 KHz. Experimental verification results are described.

  • dead zone Digital Controller for improved dynamic response of power factor preregulators
    Applied Power Electronics Conference, 2003
    Co-Authors: Aleksandar Prodic, Dragan Maksimovic, Robert W Erickson
    Abstract:

    This paper presents a simple control method for improvement of dynamic responses in a Digitally controlled low-harmonic rectifier with power factor correction (PFC). The Controller uses a fixed or self-adjusting dead zone in analog-to-Digital conversion to eliminate the output capacitor ripple from the voltage control loop. The proposed control methods are tested in a completely Digitally controlled 200 W boost PFC operating at 200 kHz switching frequency. Experimental results show that the simple Controller implementation results in low current harmonics and significantly improved output voltage transient responses.

  • high frequency Digital Controller ic for dc dc converters
    Applied Power Electronics Conference, 2002
    Co-Authors: Benjamin James Patella, Aleksandar Prodic, A Zirger, Dragan Maksimovic
    Abstract:

    This paper describes a complete Digital Controller IC for high-frequency switching converters. Novel architecture and configurations of the key building blocks: A/D converter, compensator and Digital pulse-width modulator, are introduced to meet the requirements of tight output voltage regulation, highspeed dynamic response, and programmability without external passive components. The implementation techniques are experimentally verified on a prototype chip that takes less than 1 mm/sup 2/ of silicon area in a standard 0.5 /spl mu/ Digital CMOS process and operates at the switching frequency of 1 MHz.

  • mixed signal simulation of Digitally controlled switching converters
    2002 IEEE Workshop on Computers in Power Electronics 2002. Proceedings., 2002
    Co-Authors: Aleksandar Prodic, Dragan Maksimovic
    Abstract:

    In this paper we give an overview of tasks, models and mixed-signal simulation tools to support design of Digitally controlled switching power supplies where the Digital Controller is implemented in a dedicated FPGA or ASIC. Mixed-signal simulation models of a Digitally controlled switching converter based on Matlab/Simulink and HDL/Spice simulation tools are presented. The models are used in the design of a high-frequency Digital Controller integrated circuit for DC-DC switching converters. Simulation and experimental results are compared.

Praveen Jain - One of the best experts on this subject based on the ideXlab platform.

  • a low complexity dual voltage loop Digital control architecture with dynamically varying voltage and current references
    IEEE Transactions on Power Electronics, 2014
    Co-Authors: Shangzhi Pan, Praveen Jain
    Abstract:

    In this paper, a low-complexity dual-voltage-loop Digital control architecture is presented for voltage regulators (VRs), delivering power to processors. The proposed Digital control architecture uses low speed and less complex Digital-to-analog converters instead of high-speed analog-to-Digital converters, thus significantly reducing the system complexity and cost. In this control architecture, there are two voltage loops, and the voltage reference is dynamically generated to selectively track one of them, as compared to other control methods where the output voltage tracks the voltage reference. Moreover, a straightforward control law is used, which does not require any compensator, making the proposed Digital architecture simple and easy to implement. The dual-voltage-loop architecture breaks dependence between the system transient response and the system control bandwidth. One voltage loop is designed for the stable system operation, and the other is dedicated for the load transient response. Thus, the Digital Controller can be designed in such a way that the VR operates at a relatively low switching frequency to reduce power losses, and at the same time, it is also able to provide fast transient response. The proposed small signal model reveals that the inner current loop is analog and the voltage loop is Digital. The proposed Controller thus can benefit from both: having valuable features of Digital control but without limitations such as limit cycle, which is eliminated by the inherent dithering characteristic. Theoretical, simulation and experimental results prove the effective operation and excellent dynamic performance of the low-complexity Digital Controller, thus making it a valuable candidate for a high-volume, low-cost Digital Controller for processors' VRs.

  • application and stability analysis of a novel Digital active emi filter used in a grid tied pv microinverter module
    IEEE Transactions on Power Electronics, 2013
    Co-Authors: Djilali Hamza, Praveen Jain
    Abstract:

    This paper presents a novel technique to suppress common-mode electromagnetic interference (EMI) using a Digital active EMI filter (DAEF). The DAEF control technique is concurrently implemented with a Digital Controller of a grid-tied photovoltaic microinverter. A brief description of the microinverter architecture and its inverter circuit is illustrated. The inverter stability is investigated using the overall transfer function. Accordingly, the system compensation is designed based on the direct quadrant (DQ) reference frame control technique. Finally, the proposed Digital Controller is tested on a grid-connected 200-W dc-ac microinverter. The experiment results validate the effectiveness of the proposed technique. Compared with the conventional passive EMI filter, the proposed Digital Controller can achieve an equivalent or better performance in terms of EMI suppression and maintain stability within the operation bandwidth. Therefore, the embedded DAEF can significantly reduce the size, cost, and space of the overall power inverter printed circuit board without the need of a conventional passive EMI filter.

H Jin - One of the best experts on this subject based on the ideXlab platform.

  • high performance predictive dead beat Digital Controller for dc power supplies
    IEEE Transactions on Power Electronics, 2002
    Co-Authors: Stephane Bibian, H Jin
    Abstract:

    In this paper, a Digital control technique based on a two-loop predictive dead-beat control concept is developed for switchmode DC/DC power supply applications. The dead-beat control law is derived directly from the switching characteristic of the converter. With the inductor current reaching the reference in a single control period, the proposed technique results in much improved control performance. In addition, the design procedure is simple and does not require extensive tuning. Furthermore, the computational resources required for the calculation of the control algorithm are reduced by half as compared to a conventional digitized PI structure. Both experimental and simulated results are provided to validate the proposed concept.

  • high performance predictive dead beat Digital Controller for dc power supplies
    Applied Power Electronics Conference, 2001
    Co-Authors: Stephane Bibian, H Jin
    Abstract:

    In this paper, a Digital control technique based on a predictive dead-beat control concept is developed for switch-mode DC/DC power supply applications. As compared to a conventional Digital Controller, the proposed technique offers much improved control performance. In addition, the design procedure is simplified and the computational resources required for the calculation of the control algorithm are significantly reduced.

  • Digital control with improved performance for boost power factor correction circuits
    Applied Power Electronics Conference, 2001
    Co-Authors: Stephane Bibian, H Jin
    Abstract:

    In this paper, an approach for the design of a Digital Controller for a PFC pre-regulator is proposed. The Controller is modified to account for large control periods and computational delays, and can therefore be implemented on processors with few available computational resources. Results show that, even with a very low control rate, system specifications can be met using the proposed technique.

  • Digital Controller design for switchmode power converters
    Applied Power Electronics Conference, 1999
    Co-Authors: Y Duan, H Jin
    Abstract:

    A thorough and systematic evaluation of different Digital control design approaches is presented. The performance of the approaches is compared in terms of both the bandwidth and the phase margin of the control loop, as well as the output transient response subject to line and load step change. Furthermore, the difference of these design approaches under a lower sampling rate is studied. Best Digital design approach for power converter applications is identified based on the comparison results.

Djilali Hamza - One of the best experts on this subject based on the ideXlab platform.

  • application and stability analysis of a novel Digital active emi filter used in a grid tied pv microinverter module
    IEEE Transactions on Power Electronics, 2013
    Co-Authors: Djilali Hamza, Praveen Jain
    Abstract:

    This paper presents a novel technique to suppress common-mode electromagnetic interference (EMI) using a Digital active EMI filter (DAEF). The DAEF control technique is concurrently implemented with a Digital Controller of a grid-tied photovoltaic microinverter. A brief description of the microinverter architecture and its inverter circuit is illustrated. The inverter stability is investigated using the overall transfer function. Accordingly, the system compensation is designed based on the direct quadrant (DQ) reference frame control technique. Finally, the proposed Digital Controller is tested on a grid-connected 200-W dc-ac microinverter. The experiment results validate the effectiveness of the proposed technique. Compared with the conventional passive EMI filter, the proposed Digital Controller can achieve an equivalent or better performance in terms of EMI suppression and maintain stability within the operation bandwidth. Therefore, the embedded DAEF can significantly reduce the size, cost, and space of the overall power inverter printed circuit board without the need of a conventional passive EMI filter.

  • Implementation of a Novel Digital Active EMI Technique in a DSP-Based DC–DC Digital Controller Used in Electric Vehicle (EV)
    IEEE Transactions on Power Electronics, 2013
    Co-Authors: Djilali Hamza, Majid Pahlevaninezhad, Praveen K. Jain
    Abstract:

    With ever increasing green-house gas emissions from fossil fuel-driven automobiles leading to acute environmental pollution, and ever depleting reserves of fossil fuel, today need for the development of pure electric vehicle (EV) is of utmost importance. Presently, there is an immense impetus to develop plug-in EVs. High switching frequency and high-power ac-dc PFC converter with an isolated output and a dc-dc isolated converter are essential systems for transferring from utility mains to the different battery packs which store energy for propelling the EVs. Electromagnetic compatibility (EMC) with strict regulatory standards is an essential requirement which any switch mode power converter must comply with not only for its own operation but also for safe and secure operation of surrounding electrical equipment. EVs possess many sophisticated electronic circuits in the vicinity of the battery charging power converters, so strict EMC standards of the on-board power converters should be met. For a cost-effective design approach, EMC should be considered at the primitive stages of the power converter design. The most commonly used passive electromagnetic interference (EMI) filters used for EMI mitigation in power converters come at the expense of cost, size and weight, power losses, and printed circuit board (PCB) real estate. In this paper, a novel embedded Digital active EMI filter (DAEF) integrated into the DSP-based Digital Controller of a dc-dc converter applicable for charging the low-voltage battery bank of an EV is proposed and analyzed. Experimental results and comparison of the performance of the proposed embedded DAEF with a conventional EMI filter are presented in this paper so as to validate the feasibility of the proposed EMI filter and its advantages over the conventional one.