PESC Record - IEEE Annual Power Electronics Specialists Conference

Publications in this journal

• Conference Proceeding: General control for boost PFC converter from a sliding mode viewpoint

  G. Chu, Siew-Chong Tan, C.K. Tse, Siu Chung Wong
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  ABSTRACT: In this paper, we propose a current control methodology for the boost PFC converter based on sliding mode control theory. The resulting control is very general in the sense that it provides input current tracking under all practical conditions by systematically including all necessary control functions that compensate for the possible nonlinearity such as the zero-crossing distortion in high line frequency condition. By choosing suitable state control variables and a proper sliding surface, the derivation arrives at a feedforward control which is similar to a previously proposed method. The implementation takes the form of a typical pulse-width modulation (PWM) control. It can be designed either as an individual current controller or as feedforward control applied to a standard PFC controller.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Source

  Available from: dartmouth.edu

  Conference Proceeding: Loss models for shaped foil windings on low-permeability cores

  J.D. Pollock, C.R. Sullivan
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  ABSTRACT: The cross section of foil windings used in ungapped, low-permeability cores can be modified to reduce total winding loss. The optimal cross-section shape is determined to have a linear cut out and a loss model is developed to calculate the winding loss in foil windings with this cross-section. The loss model shows excellent accuracy when compared to the loss determined by finite-element analysis. The loss model has been used to implement an optimization that determines the lowest loss cross-section for a particular application.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Source

  Available from: dartmouth.edu

  Conference Proceeding: Evaluation of magnetic materials for very high frequency power applications

  Yehui Han, G. Cheung, An Li, C.R. Sullivan, D.J. Perreault
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  ABSTRACT: This paper investigates the loss characteristics of several commercial rf magnetic materials forpower conversion applications in the 10 MHz to 100 MHz range. A measurement method is proposed that provides a direct measurement of inductor quality factor Q_L as a function of inductor current at rf frequencies, and enables indirect calculation of core loss as a function of flux density. Possible sources of error in measurement and calculation are evaluated and addressed. The proposed method is used to identify loss characteristics of different commercial rf magnetic core materials. The loss characteristics of these materials, which have not previously been available, are illustrated and compared in tables and figures. The results of this paper are thus useful for design of magnetic components for very high frequency applications.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: Robust current assisted H∞ controller for boost converter in the presence of uncertainty and evaluation using μ-analysis

  G.C. Ioannidis, S.N. Manias
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  ABSTRACT: A novel current assisted H_infin controller for boost converter is presented in this paper. The proposed controller combines the H_infin robust stabilization technique and classical loop-shaping. The current loop of the boost converter is closed with constant gain and then, the H_infin controller is estimated and applied to the converter, closing the voltage loop. The derived controller has been compared to the popular peak current mode controller in terms of robust stabilization and performance using the concept of uncertainty and the powerful tool of mu-analysis. To verify the theoretical analysis and conclusions, the two control schemes have been simulated under nominal and disturbed conditions considering step load and reference changes.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: An isolated single stage buck-boost inverter

  Liang-hua Zhang, Xu Yang, Xiaofeng Yao
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  ABSTRACT: This paper presents a novel isolated single stage buck-boost inverter for implementing dc-to-ac, ac-to-dc or dc-to-dc. The BBI has better performances, in terms of low cost, high efficiency and high voltage gain. Through the HEV/EV application, the circuit operation principles and characteristics have been analyzed. And then, a novel Synchro-Switching SVPWM have been presented to obtain the maximum buck-boost factor and ZVS or ZCS conditons on the main switches and to reduce the magnetizing inductance value of transformer. The experimental results have confirmed the operating principle and the analysis method.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: Adaptive control of power converters by switched capacitors filters

  P.G. Maranesi, M. Riva, F. Belloni
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  ABSTRACT: An analog adaptive controller of power converters based upon a switched capacitor programmable filter is described. The transfer function of the external feedback network is continuously updated by the readouts of the input variables. A rough discretization of the inputs is obtained by a small number of fast comparators that digitally program the filter by means of a look-up table. The analog output drives the error amplifier of the switching converter controller whether it is PWM or phase-shifted or resonant. The present paper refers to a DC/DC converter even though the application can be addressed to any kind of power converter. The possibility of including the circuit into IC controller drivers is open. The non-linear overall characteristics of the power cells often show large differences in the dynamic behaviour depending on the operating point when the variations of the inputs are very large. The possibility of different conduction modes makes the use of a single time-invariant feedback network extremely downgrading the frequency performances. This paper describes a possible circuit topology implementing the switched capacitor adaptive feedback as a second order external network whose transfer function, in the Z domain, can assume as many different forms as required. The potential of this solution is illustrated with a simple example concerning a PWM flyback converter spanning over the discontinuous and the continuous conduction modes. The difficult work of defining the feedback transfer functions set can be carried out by an automatic analysis and CAD tool. The control of large signal transients is also made possible.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: Three-phase series active power filter without DC voltage source

  C.B. Jacobina, A.C. Oliveira, R.R. Matias, A.P.D. Queiroz
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  ABSTRACT: This paper, a three-phase series active filter without dc voltage source for voltage harmonic compensation and voltage regulation is proposed. The model of the system is derived to analyze it for general grid voltages and load conditions. Such analysis shows that it is possible to operate with a load voltage amplitude regulated at the rated reference value for some grid voltages and load conditions. Based on the system analysis, a control strategy is proposed to adequately control the system. Experimental results are presented.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: Application of hybrid PWM and passive resonant snubber for grid-connected CSI

  R.T.H. Li, H.S.H. Chung
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  ABSTRACT: A hybrid pulsewidth modulation (PWM) scheme that hybridizes the advantages of unipolar switching scheme (USS) and bipolar switching scheme (BSS) for grid-connected current source inverter (CSI) is presented. The former switching scheme has the advantage of low switching losses while the latter one has the advantage of generating output with low total harmonic distortion (THD). The inverter bridge is dominantly operated under USS over a line cycle, within which only one switch is switched at high frequency. It is momentarily operated under BSS around the zero-crossing points of the line voltage, within which two switches are switched at high frequency. To further reduce switching losses, two passive resonant snubbers are used for the high-frequency switches. The modes of operations, criteria of ensuring soft-switching and design procedures will be discussed. The proposed switching scheme and snubber structures have been successfully applied to a 900 W, 220 V, 50 Hz prototype. The controller has been implemented with DSP TMS320F2808. The steady-state characteristics of the CSI operating from half load to full load conditions will be given.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: Comparison of Medium Voltage IGBT-based 3L-ANPC-VSCs

  J.A. Sayago, S. Bernet, T. Bruckner
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  ABSTRACT: Recently the 3L-ANPC-VSC was introduced to overcome the unequal loss distribution and the resulting unsymmetrical semiconductor junction temperature distribution as main structural drawback of the 3L-NPC-VSC. This paper compares conventional 3L-NPC-VSCs with 3L-ANPC-VSCs using 3.3 kV, 4.5 kV, and 6.5 kV IGBT modules for industrial Medium Voltage Drives for rated converter output voltages of V_LL = 2.3 kV, 3.3 kV, and 4.16 kV in a switching frequency range of f_s = 300 Hz to 1050 Hz. Maximum achievable converter power, converter efficiency, switch utilization, active silicon area and material costs are determined and compared for given IGBT and diode modules. The comparison is the basis for a derivation of advantageous operating conditions of 3L-NPC-VSCs and 3L-ANPC-VSCs.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: Current-fed full bridge converter for fuel cell systems

  A. Averberg, K.R. Meyer, A. Mertens
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  ABSTRACT: This paper deals with a single phase current- fed full bridge converter with high voltage gain for fuel cell applications. The clamping circuit is implemented by an auxiliary buck converter. An analytical investigation is given, describing the operating behaviour of the converter completely. This includes a distinction of the three operating modes: continuous mode, discontinuous mode and buck mode. With the results, the impact of the input inductor choke, the transformer's winding ratio and its leakage inductance, the switching frequency and the output current on the voltage gain is emphasised. The theoretical limit of the transferable power is identified and considerations for an optimised converter design are given. To approve the analytical results, simulations are done and compared to the calculations. A 1.2 kW prototype was built and experimental results are given in this paper.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Source

  Available from: sc.edu

  Conference Proceeding: Improved online identification of switching converters using digital network analyzer techniques

  A. Barkley, E. Santi
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  ABSTRACT: Recent progress in the identification of switching power converters using an all-digital controller has granted network analyzer functionality to the control platform. In particular, the cross-correlation technique provides a nonparametric identification of a converterpsilas small-signal control-to-output frequency response. The literature shows the viability of this technique as well as a few improvements to the basic technique. This online network analyzer functionality allows new flexibility in the areas of online monitoring and adaptive control. In this paper, several improvements to the cross-correlation method of system identification are proposed which aim to further improve the accuracy of the frequency response identification, particularly at high frequencies near the desired closed-loop bandwidth. Additionally, an extension to the cross-correlation method is proposed which allows measurement of the control loop gain without ever opening the feedback loop. Thus, performance and stability margins may be evaluated while maintaining tight regulation of the output. Simulation and experimental results are shown to verify the proposed improvements.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: Integrated boost-sepic converter for high step-up applications

  Ki-Bum Park, Hyun-Wook Seong, Hyoung-Suk Kim, Gun-Woo Moon, Myung-Joong Youn
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  ABSTRACT: A general boost converter has limited voltage step-up ratio because of its parasitic resistances. Thus, it is not applicable for high step-up applications. As a solution, combining a boost converter with a series output module can be considered to supplement the insufficient step-up ratio. By applying this concept, a new integrated boost-sepic (IBS) converter, which provides additional step-up ratio with the help of an isolated sepic converter, is proposed in this paper. Since the boost converter and the sepic converter share a boost inductor and a switch, its structure is simple. Moreover, the proposed IBS converter needs no current- snubber for the diodes, since the transformer leakage inductor alleviates the reverse recovery. The operational principle and characteristics of proposed converter are presented, and verified experimentally with a 200-W, 42-V_dc input, 400-V_dc output converter prototype.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: Grid-connected PV system: Introduction to behavior matching

  M.M. Casaro, D.C. Martins
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  ABSTRACT: This paper presents a PV grid-connected system in centralized configuration and constructed with a three- phase dual-stage inverter. In this topology, usually, a DC- DC converter performs the maximum power point tracking (MPPT) and an inverter is responsible for controlling of the grid-current. For the DC-DC stage the three-phase series resonant converter (SRC3) is chosen thanks to the very advantages that it exhibit. However, it is inadequate for the accomplishment of MPPT, due that its efficiency extremely depends on the implemented deadtime and switching frequency. Then, this paper proposes a conceptual modification, i.e., a dual-stage inverter in which the inverter stage is responsible for the MPPT and the grid-current control. In addition, the DC-DC converter operates with constant duty cycle and frequency. Such configuration requires a new concept, introduced as behavior matching. It serves as fundamental feature for the DC-DC converter to reproduce the PV array I-V characteristic when they are connected, without control action. The maximum power operating point (MPOP) is finding maximizing the direct axis current, obtained by Park's transformation from the inverter, through the perturbation and observation algorithm (P&O). Any specific measurement to MPPT is made. The isolation is performed by a high-frequency transformer becoming the system most compact. The structure is appropriate for high power applications, above 10 kW.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: Polytopic black-box modeling of dc-dc converters

  L. Arnedo, D. Boroyevich, R. Burgos, F. Wang
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  ABSTRACT: The objective of this work is to develop modular black-box converter models for system-level design and analysis that are valid in a wide variety of operating conditions. The approach used to address this problem is to divide the converter operating space into sub-spaces. For each sub-space, a linear local model is constructed from frequency response functions (FRFs) measured at the converter terminals. The FRFs are then post processed using system identification, the linear models obtained are valid as a local representation of the converter intrinsic dynamic at that operating condition. In the regions where two or more adjacent linear models overlap, an appropriate weighting is applied between them to produce an accurate approximation of the measured data. This new structure allows the characterization of converters with rich nonlinear dynamics, such as an unregulated dc-dc bus converter working near the boundary region between discontinuous and continuous conduction modes or a regulated flyback dc-dc converter. These two converters are effectively modeled with the proposed approach, and its models are presented in detail, providing an in-depth description of their implementation as well as their extensive experimental validation with laboratory prototypes.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: Adaptive link voltage variation (ALVV) control for high power density adapter

  Bong-Chul Kim, Byoung-Hee Lee, Ki-Bum Park, Chong-Eun Kim, Byoung-Woo Ryu, Gun-Woo Moon, Myung-Joong Youn
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  ABSTRACT: In designing a LLC resonant converter, the ratio of magnetizing inductance (L_M) to resonant inductance (L_M), the inductor ratio (K) is usually considered. In high power density adapter, both adapter size and efficiency are important factors. considering the size of adapter, high K design can be more attractive. But, wide frequency variation of high K design results in design difficulty of magnetic elements and decrease in efficiency. To solve these drawbacks, an adaptive link voltage variation (ALVV) control is proposed. With the proposed control method, the LLC resonant converter can be operated at the resonant frequency despite the output voltage variation. The control strategy and schematics are presented, and verified experimentally.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: Model predictive control of multiphase interleaved DC-DC converters with sensorless current limitation and power balance

  S. Mariethoz, A.G. Beccuti, M. Morari
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  ABSTRACT: The present paper investigates the control of interleaved DC-DC converters. It proposes an alternative solution to balance the currents between the legs without using current transducer, relying instead on a feedback loop based on the measurement of the capacitor voltage ripple. The appropriate measurement circuit is proposed. The voltage control uses a model predictive control scheme, which assumes the average model of a single leg converter, the unbalance being compensated separately. The controller intrinsically limits the current during transients, achieving protection of the semiconductor devices and avoiding coil saturation. The proposed control and balance methods are validated experimentally on a two-leg interleaved converter.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: An iZVT auxiliary circuit commutation applied to a double conversion uninterruptible power supply

  A.T. de Oliveira, J.L. Russi, J. Renes Pinheiro
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  ABSTRACT: In this paper it is proposed an iZVT circuit using the concept of integrated ZVT auxiliary commutation circuits (iACC) applied to a double-conversion uninterruptible power supply, operating with a Three-Level PWM Full Bridge inverter. This study has two objectives: to reduce the number of additional components necessary to obtain soft-switching as well as to minimize the circulating reactive energy by means of reusing the reactive energy of one commutation to assist another one, so that the efficiency improves without penalizing the cost. Thus, it is obtained ZVT commutation for all the main switches and ZCS and ZVS for the auxiliary switches. To demonstrate the technique of iACC applied to a double-conversion UPS, experimental results of the system rated at 1.2 kW - 70 kHz are presented. The efficiency comparison between iZVT UPS and the ZVT UPS is shown, justifying the proposed iZVT.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: Modeling and power conditioning for thermoelectric generation

  Lihua Chen, Dong Cao, Yi Huang, F.Z. Peng
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  ABSTRACT: In this paper, the principle and basic structure of the thermoelectric module is introduced. The steady- state and dynamic behaviors of a single TE module are characterized. An electric model of TE modules is developed and can be embedded in the simulation software for circuit analysis and design. The issues associated with the application of the TEG models is analyzed and pointed out. Power electronic technologies provide solutions for thermoelectric generation with features such as load interfacing, maximum power point tracking, power conditioning and failed module bypassing. A maximum power point tracking algorithm is developed and implemented with a DC-DC converter and low cost microcontroller. Experimental results demonstrated that the power electronic circuit can extract the maximum electrical power from the thermoelectric modules and feed electric loads regardless of the thermoelectric module's heat flux and load impedance or conditions.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008
• Conference Proceeding: An improved model for the high frequency resistance of non-layered windings

  G. Dimitrakakis, E. Rikos, E. Tatakis
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  ABSTRACT: An improved model for the calculation of high frequency resistance of windings that show an arbitrary conductor distribution within the available window space is presented. The new formula, which is extracted after an extensive process of Finite Element Analysis simulations, followed by statistical treatment of the results, is verified by experimental measurements on windings wound over cores with circular as well as rectangular center pole. In this way an easily applicable tool is offered to help the optimization of magnetic components when non-layered coils are used.
  Power Electronics Specialists Conference, 2008. PESC 2008. IEEE; 07/2008