Table of contents monday, September 9, 1: 30pm-4: 00pm modular Multi-Level Converters, hvdc, and dc grids I 3
Yüklə 2,78 Mb.
|
- Bu səhifədəki naviqasiya:
- Single-Phase Inverters
- DC-DC Converters I
- DC-DC: Dual Active Bridge
| 1:55PM The Power-Loss Analysis and Efficiency Maximization of A Silicon-Carbide MOSFET Based Three-phase 10kW Bi-directional EV Charger Using Variable-DC-Bus Control [#30]
Kevin (Hua) Bai, Chenguang Jiang, Hui Teng and Bo Lei, Kettering University, United States It is expected that wide-bandgap devices like silicon carbide MOSFETs and gallium nitride HEMTs could replace Si devices in power electronics converters to reach higher system efficiency, e.g., a 3-phase 380VAC bidirectional battery charger for electric vehicles. This paper uses the conventional half-bridge LLC topology to build a 10kW all-SiC bidirectional charger. As a well-known topology for the unidirectional charger, it has not been comprehensively explored for the usage of the bidirectional energy flow, which falls into the scope of this paper. A double-pulse-test platform is utilized to provide the accurate power losses, which, combined with the state-space model deriving the accurate switching current waveforms eventually accurately, estimates the system efficiency. Based on this model, to further enhance the system efficiency the DC-bus voltage is varied while keeping the LLC DC-DC converter running at the resonant frequency through the whole power range. Experimental results validated our proposed approach that such topology could realize the bidirectional power flow with zero- voltage-switching turn on. With varying the DC-bus voltage, the V2G and G2V modes reach 96% wall-to-battery efficiency. 2:20PM Modular Multi-Parallel Rectifiers (MMR) with two DC Link Current Sensors [#16]
Conventional three-phase diode or controlled rectifiers generate current harmonics which affect power quality of distribution networks. This paper presents a novel topology with a front end Modular Multi-Parallel Rectifiers (MMR): Active DC link current controllers are utilized for each rectifier connected to a common DC link capacitor which can reduce line current harmonics emissions significantly. In the proposed topology, two current sensors are utilized in DC link legs to reduce switching ripples of the DC link currents. Analysis and simulations have been carried out to verify the proposed topology and operating modes. 2:45PM Comparison of Three-phase Active Rectifier Solutions for Avionic Applications: Impact of the Avionic Standard DO-160 F and Failure Modes [#1157]
In aircraft applications, there has been an increasing trend related with the More Electric Aircraft (MEA), which results in rapid rise in the electrical power demand on-board. One of its goals lies in minimizing weight and volume of the electrical subsystem while maintaining good power quality and efficiency. The main purpose of this paper is to present and analyze an electrical design of a three-phase Boost rectifier, a three-phase Buck rectifier and a three-phase Vienna rectifier for output power level of 10 kW and compare them in terms of weight, volume, efficiency etc. Moreover, the design is obliged to comply with specific sections of DO-160 standard for avionic equipment with 230 VAC, 360-800 Hz grid conditions. Even though all proposed solutions satisfy the standard requirements, it will be shown that the Vienna rectifier has the lowest volume and not considering failure modes, the better solution overall. However, due to increased number of semiconductors and additional circuitry required for soft start-up, the Buck rectifier would prove to be the more robust solution failure-wise. 3:10PM MultiLevel Asymmetric Single-Phase Current Source Rectifiers [#1611]
In this work it is presented a review of the Multilevel Current Source Rectifiers (MCSR), aiming to reduce the number of switches and inductors, thus reducing losses, cost and volume of the converter. Despite the removal of switches and inductors, the control and PWM ensures the correct operating of the converter. Simulations are presented to validate the effective operation of the topology for five-, seven- and nine-level MCSR and experimental results are presented for the five-level topology, using a prototype converter built in laboratory. 3:35PM Three-Phase Unidirectional Rectifiers with Open-End Source and Cascaded Floating Capacitor H-Bridges [#1020]
This paper presents two topologies of three-phase semi-controlled rectifiers suitable to open-end configured ac power sources. The rectifiers are composed by a combination of two-level three-phase bridges (controlled, semi-controlled ou uncontrolled), and three single-phase floating capacitor H-bridges. These topologies generate two powered dc-links, each one belonging to a three-phase bridge. They present a reduced number of controlled power switches if compared to other open-end configurations of similar complexity found in the literature. Besides the topologies and dedicated to them, it is proposed a Space Vector Pulse Width Modulation (SV-PWM) approach and a method of floating capacitor voltage control. The PWM approach provides a method for redundancy selection, which allows the floating capacitors voltage regulation by means of the redundant state selection (RSS) technique. Simulation results are shown to validate the proposed topologies, the SV-PWM resolution technique and the control strategy. Single-Phase Inverters Monday, September 19, 1:30PM-4:00PM, Room: 203AB, Chair: Aaron Cramer, Roberto Petrella 1:30PM A Generic Topology Derivation Method for Single-phase Converters with Active Capacitive DC-links [#1542] Haoran Wang, Huai Wang, Guorong Zhu and Frede Blaabjerg, Aalborg University, Denmark; Wuhan University of Technology, China Many efforts have been made to improve the singlephase power converters with active capacitive DC-link. The purpose is to reduce the overall DC-link energy storage and to achieve a reliable and cost-effective capacitive DC-link solution. A few review papers have already discussed the existing capacitive DC-link solutions, but important aspects of the topology assessment, such as the total energy storage, overall capacitive energy buffer ratio, cost, and reliability are still not available. This paper proposes a generic topology derivation method of single-phase power converters with capacitive DC-links, which derives all existing topologies to our best knowledge, and identify a few new topologies. A reliability-oriented design process is applied to compare the cost of different solutions with the lifetime target of 10 years and 35 years, respectively. It reveals that the most cost-effective solutions varies with the lifetime target. 1:55PM Power Decoupling Method for Single Phase PV System using Cuk derived micro-inverter [#529]
Power decoupling is required to balance the difference between constant power at PV side and double frequency pulsating power at load side in single phase AC system. The balance power is generally handled by circuit passives. This paper proposes decoupled power control for grid connected PV systems using an embedded decoupling capacitor in a doubly grounded boost buck (Cuk) derived micro inverter. The method ensures smaller size of PV terminal capacitor, absence of transformer and also removes the potential hazard to humans in contact with the PV array. Simulation and experimental both result verify the circuit operation and analysis. 2:20PM A Multi-port, Isolated PV Microinverter with Low Decoupling Capacitance and Integrated Battery Charger [#1073]
This paper proposes a dual-active bridge (DAB)-based isolated microinverter topology with integrated energy storage capability. A control strategy involving dynamic variation of the phase-shift allows twice line frequency energy buffering to be handled on the high-voltage secondary side, resulting in considerable reduction in decoupling capacitance requirement. Being a DAB- derived structure, most of the devices have the possibility of undergoing zero-voltage-switching (ZVS) turn-on. The topology has further advantages of the battery and PV port currents having very less high-frequency ripple on account of them being inductively interfaced. Working principle of the circuit is first described followed by an explanation of the control scheme. Circuit operation is verified through simulations and open-loop experimental tests on a 250 W hardware prototype. 2:45PM A Single Phase Transformerless String Inverter with Large Voltage Swing of Half Bridge Capacitors for Active Power Decoupling [#1485]
The transformerless single phase inverters are becoming common due to its advantages of reduced volume, lower cost, and higher efficiency but it has two implementation challenges- high frequency capacitive ground current and decoupling of double line frequency power. This paper proposes an optimized power decoupling topology for a single phase string inverter which addresses both the challenges as well as minimizes capacitance required to decouple the ripple power. Unlike conventional power decoupling techniques in full bridge converters, the proposed technique does not significantly increase the voltage stress on the devices. The combination of a half-bridge inverter and a buck boost converter ensure the complete elimination of high frequency capacitive coupled ground currents. The proposed technique requires only 40 uF/kW at 600 V for power decoupling. A closed loop controller design for the converter is detailed and the experimental results at 1 kW, 120 V, 60 Hz output for closed loop operation are provided. 3:10PM A-Source Impedance Network [#469]
A novel A-source impedance network is proposed in this paper using an autotransformer for realizing converters that demand a very high dc voltage gain. The network utilizes a minimal turns ratio compared to other Magnetically Coupled Impedance Source (MCIS) networks to attain high voltage gain. In addition, the proposed converter draws a continuous current from the source, and hence it is suitable for many types of renewable energy sources. This voltage boost capability has been demonstrated by mathematical derivations, and it is also realized in experiments with an example single-switch 50 kHz, 200 W dc-dc converter. 3:35PM A Semi-Two-Stage DC-AC Power Conversion System with Improved Efficiency Based on A Dual-input Inverter [#218]
A semi two-stage DC-AC power conversion system composed of a Boost DC/DC converter and a novel dual-input inverter is presented in this paper. The low voltage DC source and the output of the Boost DC/DC converter are used as the low-voltage and high-voltage DC input ports, respectively, of the dual-input inverter. So part of the input power can be supplied to the inverter directly and will not be processed by the front-end Boost converter. As a result, the conversion stage, power/current stresses of the Boost converter, and associated power losses are reduced, and the overall conversion efficiency is improved. In addition, the two input ports provide a multi-level voltage to the inverter, which will lower the voltage stresses and switching losses of the switching devices. A 1000W prototype is built and tested to verify effectiveness and advantages of the presented semi two-stage power conversion system. DC-DC Converters I Monday, September 19, 1:30PM-4:00PM, Room: 102C, Chair: Praveen Jain, Liangzong He 1:30PM Single-Input Multiple-Output Synchronous dc-dc Buck Converter [#1258] Bharath Kumar Sabbarapu, Omar Nezamuddin, Andrew McGinnis and Euzeli dos Santos, Indiana University-Purdue University-Indianapoli, United States This paper proposes a new single-input three-output DC-DC buck converter. The proposed topology has two less switching devices than that of a conventional converter. This reduction in switching devices results in lower cost and a more even distribution of power losses among the switching devices. A comprehensive small signal Modeling and control strategies for the proposed converter will be presented. Simulation and experimental results are presented to validate the theoretical expectations. The simulation is performed using PSIM, and the laboratory experiment is performed with a proof of concept prototype. 1:55PM Dual-Input Dual-Output Single-Switch Dc-Dc Converter for Renewable Energy Applications [#533]
Normally, a photovoltaic energy generation system is composed of dc-dc converter, dc-ac converter, and their corresponding control circuits. This paper presents a two-input two-output single switch dc-dc converter with a reduced number of switches, drivers and controllers. The proposed converter performs independent energy flux control for each dc input while producing two symmetrical, automatically balanced, output voltages. A very simple MPPT technique, based on fractional voltage control technique, is employed to confirm the performance of proposal. Simulation and experimental results verify the proposed scheme feasibility. 2:20PM A High Step-Up Interleaved Converter with Coupled Inductor and Voltage-Lift Technique [#261]
This paper proposes a high step-up interleaved converter with coupled inductor and voltage-lift technique. The proposed converter achieves high voltage gain by employing coupled inductor and voltage-lift technique. Moreover, low input current ripple is realized by using interleaved technique. The energy in the leakage inductance of the coupled inductor is recycled to the output load. The voltage stresses on the main switches are reduced and the voltage spikes across the main switches are alleviated. This paper shows a theoretical analysis in steady-state and experimental results with a small-scale prototype circuit. 2:45PM Single Resonant Cell Based Multilevel Soft-Switching DC-DC Converter for Medium Voltage Conversion [#273]
A multilevel soft-switching DC-DC converter with only one resonant cell for medium voltage conversion is proposed in this paper. Two control strategies for the converter are analyzed and compared. For the proposed converter, all dc capacitors can achieve voltage self-balanced under open loop control. All switches and diodes operate in soft-switching condition without sacrificing reliability. Finally, a prototype of a four-level DC-DC converter is given and the validity of the converter is verified by experimental results. 3:10PM Unified Model of High Voltage Gain DC-DC Converter with Multi-cell Diode-Capacitor/Inductor Network [#1364]
Multi-cell diode-capacitor/inductor based boost derived DC-DC converter provides a simple solution for high step-up voltage regulation in solar and fuel cell generation. However, many passive components increase the order of system model and complexity. Transient modeling analysis reveals that time constant of each component in diode-capacitor/inductor network is much smaller than that of other circuit if the directly charging and discharge processes between capacitor through diode is fast enough. The voltage/current relationship of each capacitor/inductor in multi-cell network is fixed. Multi-cell diode-capacitor/inductor network can be seemed as multi-stage DC transformer. Based on the unique feature, this paper proposes the reduced-order modeling approach for high step-up DC-DC converter with multi-cell diode-capacitor/inductor network. Finally, simulation and experiments verify the correctness and effectiveness of new modeling approach. The unified reduced-order model contributes to better understanding of circuit characteristic and simplification of controller parameters design. 3:35PM Comparative Evaluation of a Triangular Current Mode (TCM) and Clamp-Switch TCM DC-DC Boost Converter [#1011]
For the power management of a wireless power transfer system for implantable mechanical heart pumps, an additional boost DC-DC converter stage is needed in order to control the power delivered to the implant. Particularly, battery powered and implantable medical devices pose special demands on the efficiency and/or power density of the employed converters. Accordingly, soft-switching and/or high switching frequencies must be targeted. Modulation schemes that allow for Zero-Voltage-Switching (ZVS) such as Triangular Current Mode (TCM) offer a highly efficient operation, but suffer from a large operating frequency variation, which is mainly limited by the digital control. Therefore the Clamp-Switch TCM (CL-TCM) converter can be employed which allows also for the control of the switching frequency variation. In this paper, the CL-TCM and the TCM converter are compared regarding the power conversion efficiency and the power density of the converter. Since the CL-TCM converter is not well known in the literature, the converter is analysed in detail and a modulation scheme is explained that allows for ZVS for all switches in the entire range of operation. In addition, the requirements for ZVS and a control scheme (i.e. timing calculations) are provided for the converter in order to limit the maximum switching frequency. The modulation and control scheme are verified with a hardware prototype. Finally, the performance of the CL-TCM converter is measured and compared to the performance of the converter operated in TCM mode. The measurements show that the CL-TCM converter offers similar performance compared to the TCM operation at lower inductor power density, but has the advantage of a significantly reduced switching frequency variation. In applications, where a very high power density is needed, the TCM converter outperforms the CL-TCM converter in terms of efficiency. DC-DC: Dual Active Bridge Monday, September 19, 1:30PM-4:00PM, Room: 102E, Chair: Regan Zane, Zhiqiang Guo 1:30PM Analytically Constrained ZVS Operation To Reduce Commutation Losses for High Boost Dual-Active Bridge Converters [#814] Jan Riedel, Donald Grahame Holmes, Brendan Peter McGrath and Carlos Teixeira, Robert Bosch (SEA) Pte Ltd, Singapore; RMIT University, Australia Dual Active Bridge (DAB) converters offer an unmatched capability to transfer energy in either direction between two DC sources, especially when they are operated under Zero Voltage Switching (ZVS) conditions. However, the parasitic commutation inductance within the bridge phase leg devices can still lead to significant energy losses at device turnoff despite operating under ZVS conditions. These losses can become significant when one bridge has a low DC bus voltage and a consequential high magnitude output current. This paper shows how harmonic decomposition analysis can be used to constrain the bridge circulating currents to their minimum possible values at the point of phase leg commutation while still ensuring that ZVS operation is maintained. This can be used to improve the overall DAB performance under low voltage, high current operating conditions of one DC port. The capability of the theoretical analysis process is confirmed by matching experimental results for a reference DAB system. 1:55PM Passive Auxilliary Circuit for ZVS Operation of A Wide-DC-Range Dual-Active-Bridge Bidirectional Converter for Transportation Applications [#1477]
In this paper, an isolated bidirectional converter is proposed for transportation applications such as midsize electrified airplanes. Using time- domain analysis a modulation scheme is suggested that allows the converter to transfer any power level up to the nominal value over the entire wide dc range of terminal voltages. A single robust and low cost passive auxiliary is introduced to guarantee zero voltage switching of all the eight switches for any combination of dc voltage and power levels. Effectiveness of the modulation scheme in achieving zero current switching was experimentally confirmed. 2:20PM Charge-Based ZVS Modulation of a 3-5 Level Bidirectional Dual Active Bridge DC-DC Converter [#661]
This paper presents a charge-based Zero Voltage Switching (ZVS) modulation strategy for the 3 Level - 5 Level (3-5L) Dual Active Bridge (DAB) DC-DC converter. The DAB combines a primary-side full bridge and a secondary side mixed bridge (i.e. a 3-level T-type leg with a half-bridge leg), linked by a high-frequency transformer and an inductor. A ZVS modulation strategy is presented, in which a charge-based model of the non-linear parasitic output capacitances of the switches is used to accurately describe the ZVS constraints. Moreover, commutation inductances are included to extend the ZVS region to the entire operating range. The configuration of the secondary-side bridge facilitates increased flexibility compared to a full bridge configuration, in order to reduce the RMS current in the switches, inductor, and transformer. The nominal power of the investigated converter is 2.8 kW with input voltage range from 8 V to 16 V and output voltage range from 175 V to 450 V. The RMS currents of the 3-5L DAB are compared with those of a typical 3-3L DAB, applying the proposed modulation strategy in the 3-5L DAB, and a similar strategy previously proposed in literature in the 3-3L DAB. 2:45PM Parallel-Connected Bidirectional Current-Fed Dual Active Bridge DC-DC Converters with Decentralized Control [#76]
A decentralized control strategy with improved droop control is proposed for parallel-connected current-fed bidirectional DC-DC converters to achieve the flexible power architecture and modular design. The step-up or step-down function depends on the power flow direction. An improved droop control strategy is implemented by sensing the high-voltage side (HVS) voltage and low-voltage side (LVS) current. The operation principle and power sharing characteristics are analyzed. The system stability is demonstrated in detail based on small-signal model. Excellent power sharing can be achieved not only under steady state but also in dynamics. Besides, the system has the hot-swapping feature. A 2.5kW prototype composed of two modules is established to verify the effectiveness of the proposed control strategy.
Yüklə 2,78 Mb. Dostları ilə paylaş:
|