Advanced electrical power, distribution and control for the Space Transportation System

High frequency power distribution and management is a technology ready state of development. As such, a system employs the fewest power conversion steps, and employs zero current switching for those steps. It results in the most efficiency, and lowest total parts system count when equivalent systems are compared. The operating voltage and frequency are application specific trade off parameters. However, a 20 kHz Hertz system is suitable for wide range systems

Zero-Voltage and Zero-Current Switching Buck-Boost Converter for PV Applications

A ZVS and ZCS buck boost converter is presented for PV panel applications. The salient points are that all the switching devices are under zero-current switching during turn-on and zero-voltage switching during turn-off. The active switches in the converter undergo zero-capacitive turn-on losses unlike switches in other soft-switched topologies. The switches do not experience any over voltage/over current stress proportional to load as in resonant converters. This soft-switching technique can also be applied to other classical switched mode power converters. A detailed analysis of the converter under steady state is discussed and simulation results obtained are presented

Power Converter Possessing Zero-Voltage Switching and Output Isolation

A modified boost converter accomplishes power transfer to a load with an electrical isolation, a zero-voltage and a zero-current switching, a transformer core resetting mechanism, and component stresses identical to those in the conventional boost converters. The power converter contains two switching devices, a main one connected in parallel and a secondary one connected in series with a transformer primary winding. A secondary winding of the transformer is connected through an output rectifier to the load. Zero-voltage switching and proper transformer-core resetting are achieved from the resonance that exists between the parasitic capacitance of the secondary switching device and the magnetization inductance of the transformer. A transformer leakage inductance facilitates zero-current switching; thus, reducing the recovery time and current in the output rectifier, and the turn-on switching loss in the conventional main switching device. The switching converter contains a lossless cl

Control and performance of a zero-current-switched three-phase inverter equipped with resonant circuits on the AC-side

This paper presents a zero-current-switched voltage-fed inverter equipped with resonant circuits on the AC side. The current flowing through a switching device, i.e., an IGBT is a sum of the load current and the resonant current. If the amplitude of the resonant current is larger than that of the load current, the current in a switching device becomes zero at an instant in each resonant cycle. This allows the switching device to be turned on or off at the zero current. The zero-current-switching makes a significant contribution to reduction of switching losses and electromagnetic noises. In this paper, the principle of zero-current-switching operation, and a novel control scheme are described from a theoretical and practical point of view. Experimental results obtained from a laboratory system of 5 kVA verify the practicability. Moreover, the efficiency and losses of the proposed soft-switched inverter are compared with those of a hard-switched inverter </p

Limit cycle bifurcations in resonant LC power inverters under zero current switching strategy

The dynamics of a DC-AC self-oscillating LC resonant inverter with a zero current switching strategy is considered in this paper. A model that includes both the series and the parallel topologies and accounts for parasitic resistances in the energy storage components is used. It is found that only two reduced parameters are needed to unfold the bifurcation set of this extended system: one is related to the quality factor of the LC resonant tank, and the other accounts for the balance between serial and parallel losses. Through a rigorous mathematical study, a complete description of the bifurcation set is obtained and the parameter regions where the inverter can work properly is emphasized.Postprint (author's final draft

Delay effects on the limit cycling behavior in an H-bridge resonant inverter with zero current switching control strategy

In this paper, bifurcations of limit cycles in a H-bridge LC resonant inverter under a zero current switching control strategy with delay in the switching action are analyzed. Mathematical analysis and numerical simulations show that the delay can degrade the quality of the oscillations and even inhibit them.Postprint (author's final draft

A Novel Application of Zero-Current-Switching Quasiresonant Buck Converter for Battery Chargers

The main purpose of this paper is to develop a novel application of a resonant switch converter for battery chargers. A zero-current-switching (ZCS) converter with a quasiresonant converter (QRC) was used as the main structure. The proposed ZCS dc–dc battery charger has a straightforward structure, low cost, easy control, and high efficiency. The operating principles and design procedure of the proposed charger are thoroughly analyzed. The optimal values of the resonant components are computed by applying the characteristic curve and electric functions derived from the circuit configuration. Experiments were conducted using lead-acid batteries. The optimal parameters of the resonance components were determined using the load characteristic curve diagrams. These values enable the battery charger to turn on and off at zero current, resulting in a reduction of switching losses. The results of the experiments show that when compared with the traditional pulse-width-modulation (PWM) converter for a battery charger, the buck converter with a zero- current-switching quasiresonant converter can lower the temperature of the activepower switch

A Fault-Tolerant T-Type Multilevel Inverter Topology with Soft-Switching Capability Based on Si and SiC Hybrid Phase Legs

The performance of a novel three-phase four-leg fault-tolerant T-Type inverter topology is presented in this paper, which significantly improves the inverter\u27s fault-tolerant capability regarding device switch faults. In this new modular inverter topology, only the redundant leg is composed of Silicon Carbide (SiC) power devices and all other phase legs are constituted by Silicon (Si) devices. The addition of the redundant leg, not only provides fault-tolerant solution to switch faults that could occur in the T-Type inverter, but also can share load current with other phase legs. Moreover, quasi zero-voltage switching (ZVS) and zero-current switching (ZCS) in the Si Insulated-Gate Bipolar Transistors (IGBTs) of the main phase legs can be achieved with the assistance of SiC Metal-Oxide Semiconductor Field-Effect Transistors (MOSFETs) in the redundant leg. Simulation and experimental results are given to verify the efficacy and merits of this high-performance fault-tolerant inverter topology

A zero-current-switching based three-phase PWM inverter having resonant circuits on AC-side

The authors present a zero-current-switching (ZCS)-based three-phase PWM (pulse-width-modulated) inverter having small resonant circuits on the AC side, whose resonant frequency is 50 kHz. The ZCS inverter can greatly reduce the switching losses and electromagnetic noise. The principle of ZCS operation, the design of the resonant circuits, and the control sequence are described from theoretical and practical points of view. Experimental results obtained from a ZCS PWM inverter driving an induction motor of 2.2 kW are shown to verify the practicability of this device </p