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In three-phase dual-active-bridge (DAB) converter, the zero-voltage-switching (ZVS) range, DC capacitor ripple current and converter efficiency are significantly impacted by the selectable system parameters, including transformer turn ratio n, switching frequency f and leakage inductance Lk. The converter performance also varies with different operation conditions, i.e., input voltage, output voltage...
The paper presents a new four-level voltage source converter (VSC). Compared to conventional four-level converters, this proposed converter has fewer components and can be used for a higher power density system in low and medium voltage applications. Its principles and advantages are studied in this paper. The effect of various redundant switching states on the voltages of flying capacitors is analyzed...
This paper proposes a transformer-less modular multilevel DC/DC converter. The proposed converter can be used to interconnect two HVDC systems with different dc voltage levels and realize bidirectional power flow. Based on the arm energy balance condition, the optimal design arming at minimum inner circulating current is presented. A power close-loop control method is adopted to regulate the converter...
Vector control is the most commonly used control strategy for modular multilevel converter (MMC) based HVDC system. However, due to the complicated structure of MMC, there is no precise mathematical model for the outer DC voltage loop. The conventional model ignores the capacitor voltage dynamics, and the AC voltage boosted operation scenario is not considered. This paper proposes a small signal model...
Modular multilevel converter (MMC) is a promising topology of Voltage Source Converter based High voltage Direct Current (VSC-HVDC) system with many outstanding advantages such as low switching frequency, low voltage distortion and harmonics. Pre-charge process is one of the core issues of MMC based system, especially for the MMC with DC fault blocking capability. In this paper, considering a novel...
The multilevel converter is a prospective topology for both Medium Voltage and High Voltage Direct Current (HVDC) applications. In high power application, the forward topology is applied to increase the power region. In this paper, a novel forward-mode five-level inverter is presented which combines the features of the conventional multilevel converters and forward topology. The converters can transfer...
A passive lossless snubber for soft-switching Bidirectional Buck/boost Converter (BBC) is proposed in this paper. Although the conventional lossless snubbers can effectively alleviate the switching losses during turn on and turn off transients, they can be applied to only the unidirectional converters, but not a bidirectional converter. On the other hand, the proposed lossless snubber is able to improve...
A 4.6–5.6 GHz constant KVCO LC-VCO applied in PLL frequency synthesizer is presented in this paper. With constant KVCO LC-VCO and programmable charge pump, the frequency synthesizer is able to obtain constant bandwidth. Furthermore, the VCO has a low KVCO which will result low phase noise. An Optimized automatic frequency calibrator (AFC) is proposed, the AFC can select the sub-band which is nearest...
With the continuous development of high frequency inverter technology and multilevel inverter technology, all kinds of novel high frequency multilevel inverter are put forward and studied. And among them, the interleaved flyback three-level inverter (IFTLI) has a better work performance. In this paper, the control methods of single-phase IFTLI will be studied in-depth. Firstly, the instantaneous voltage...
A hybrid Lyapunov control for a flying capacitor multicellular converter is presented. This control law is based on the Port-Hamiltonian (PH) formalism of power converters and allows to enhance load current quality and reduce switching losses. The proposed control is applied to a three-cell multicellular converter. A procedure for selecting the best weighting parameters in the control law according...
In this paper, the energy conservation law in physics is introduced into the control prototype of boost converters. Firstly, the input and output energy and the energy changes in the reactive components in each switching cycle are analysed. Then an energy balance control (EBC) method is designed based on the energy conservation law, which is independent of converter work modes, continuous conduction...
Wireless power transfer (WPT) is the future solution for electric vehicles due to its merits compared to conductive charging. The main obstacles to WPT are efficiency and power transfer capability. Compensation topologies play a key role in improving efficiency and power transfer capability of WPT. This paper carries the evaluation of electrical parameters for wireless charging of an e-Rickshaw through...
Wireless power transfer has been introduced as a proper replacement for conventional cable power transfer systems recently. With the developments of the electric transportation, transferring power wirelessly has been found to introduce several advantages in charging Lithium-Ion batteries. Among different configurations of wireless power transfer, Series Parallel structure is found to be more interesting...
Cascaded multilevel inverter (MLI) topologies have received an attractive solution for grid connected PV system. In this paper, two-cascaded MLI topologies are presented for grid connected PV system. These are seven level cascaded H-bridge multilevel inverter and three phase cascaded voltage source multilevel inverter. In both presented MLI configurations, each PV module is connected to one DC-DC...
Reliability of power electronics is a critical issue, as most of the electrical energy is processed by power electronics. Various stressors impact the safe operation of the systems, including harsh environments, temperature variations, humidity, vibration and radiation. Physics of failure analysis uses models that describe how failure mechanisms evolve over time and induce failures. Active methods...
An open-loop and closed-loop operating boost-power-stage converter with relatively low damping factor exhibit resonant behavior in transient conditions. Such an undamped transient characteristic introduces overshoot to the control-to-output-variable transfer function, which is also visible in the inductor current transient behavior. Therefore, due to the either too large duty ratio or voltage-reference...
This paper discusses the active and reactive power control method for a modular multilevel converter (MMC) based grid-connected PV system. The voltage vector space analysis is performed by using average value models for the feasibility analysis of reactive power compensation (RPC). The proposed double-loop control strategy enables the PV system to handle unidirectional active power flow and bidirectional...
The paper proposes a three phase nine level T-type neutral point clamped (9L-T-NPC) inverter for medium voltage induction motor drive. The primary objective of the proposed inverter is to improve the output voltage quality with reduced number of devices and passive components. The generation of nine levels in the output pole voltage is achieved using only ten switches per phase. Although the similar...
This paper investigates nonlinear control methods for single-ended primary-inductor converters (SEPIC). The fast-switching and average models show the converter nonlinearity in terms of inductor currents, capacitor voltages, and the switching duty cycle. The control law intuitively should be nonlinear to drive and guarantee the system stability. Two different control laws based on the passivity and...
This paper proposes a transient modeling and analysis method for the fractional-order DC-DC converters in continuous conduction mode (CCM), in which a fractional-order Buck converter is taken as an example. By extending the usage of equivalent small parameter method (ESP), the converter is modeled by a general state vector differential equation. Then by adopting the principle of harmonic balance,...
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