A Novel Single-Switch High Step-Up DC–DC Converter with Three-Winding Coupled Inductor

This paper introduces a single-switch, high step-up DC–DC converter for photovoltaic applications such as power optimizers and microinverters. The proposed converter employs two voltage multipliers cells with switched capacitor and magnetic coupling techniques to achieve high voltage gain. This feature, along with a passive clamp circuit, reduces the voltage stress across the switch, allowing for the employment of low RDSon MOSFET. This leads to low conduction loss of the switch. The diodes operate with zero-current switching at their turn-off transition, eliminating the reverse recovery losses. Additionally, the switch turns on with zero-current switching, leading to insignificant switching loss associated with its turn-on transition. The operation principle and steady-state analysis are presented and validated through experimental results obtained from a 140 W prototype of the proposed converter.

Discontinuous Current Mode Modeling and Zero Current Switching of Flyback Converter

The flyback converters are widely used in low power applications. The switch typically requires 600 V breakdown voltage in order to perform large step-down voltage. Thus, slight variation on the switch control can either permanently damage the switch or decrease the efficiency of the power conversion. In order to achieve higher power efficiency, the previous literature suggested operating the flyback converter in the discontinuous current mode (DCM). It is then required to understand the critical conditions of the DCM through analyzing the dynamic behavior and discontinuous current mechanism. This paper started from the current waveform analyses, proceeded to the derivation of zero current switching (ZCS) formulation, and finally reached the necessary conditions for the DCM. The entire DCM operation was divided into three phases that subsequently affect the result of the zero voltage switching (ZVS) and then to the ZCS. The experiment shows a power efficiency of over 96% when the output power is around 65 W. The switch used in this paper is a Gallium Nitride High-Electron-Mobility Transistor (GaN HEMT) that is advantageous at the high breakdown voltage up to 800 V. The important findings from the experiments include that the output power increases with the increasing input DC voltage and the duty cycle is rather linearly decreasing with the increasing switching frequency when both the zero voltage switching (ZVS) and ZCS conditions are satisfied simultaneously.

Soft Switching of Non-Isolated Buck-Type Converter with Common-Ground Switch

A non-isolated buck converter, together with resonance and zero voltage transition to achieve zero voltage switching (ZVS) and zero current switching (ZCS), is presented herein to upgrade the conversion efficiency. In this circuit, the main switch and the auxiliary switch are connected to the common ground so as to make the two switches easily driven. Furthermore, these two switches take time division multiplexing operation. In addition, the pulse width modulation (PWM) control technique is utilized so as to render the output inductor and capacitor easily designed. In this paper, the theoretical derivation is first introduced, and secondly, some experimental results are provided to demonstrate the effectiveness of the proposed topology.

Continuous Control Set Model Predictive Control for an Indirect Matrix Converter

A continuous control set model predictive power control strategy for an indirect matrix converter is proposed in this paper. The load reactive power, the load active power, and the input reactive power are controlled simultaneously. This control strategy can obtain output waveforms with fixed switching frequency. Additionally, an optimal switching sequence is proposed to simplify the commutations of the indirect matrix converter. To suppress the input filter resonance, an active damping method is proposed. Experimental results prove that the proposed method features controllable input reactive power, controllable load active and reactive power, fixed switching frequency output waveforms, zero-current switching operations, and effectively suppresses input filter resonance.

SINGLE PHASE REDUCED ORDER AC-AC RESONANT- FREQUENCY CONVERTER

This paper presents the performance analysis of proposed circuit of Single-Phase Reduced Order AC-AC Resonant Frequency Converter. AC-AC converter is minimized number of switches for multi-operation and resonant converter is converter work on the principle of ZCS (Zero Current Switching) and ZVS (Zero Voltage Switching) combining both topology, which provide better output with reduce THD and switching losses. A mathematical modeling is done for proper value of used parameters in converter. The output of converter is improved by applying Modulation technique in this converter we are using Trapezoidal Pulse Width Modulation (TPWM) for the better performance and control. THD of the converter is calculated by using MATLAB simulation software. MATALB simulation of AC –AC Resonate Frequency Converter is done by using MOSFET as switch.

Vector Modulation-Based Model Predictive Current Control with Filter Resonance Suppression and Zero-Current Switching Sequence for Two-Stage Matrix Converter

This paper proposes a novel model predictive current control scheme for two-stage matrix converter. The switching frequency is kept constant by fixing the switching instant. The control strategy achieves to control source reactive power in the input side and output currents in the output side. In addition, the advantage of the proposed strategy compared with conventional model predictive control is firstly proved using the principle of vector synthesis and the law of sines in the vector distribution area. Moreover, a zero-current switching sequence is proposed and implemented to insure zero-current switching operations and reduce the switching losses. Furthermore, in order to suppress the input filter resonance, which is easier to be inspired by the model predictive control, compared with traditional control strategies, an innovative active damping technique is proposed and implemented. Finally, both simulation and experiment are implemented to verify the performance of the proposed strategy. The results demonstrate that the control system features both good steady and transient performance.

Analyzing the Effect of Parasitic Capacitance in a Full-Bridge Class-D Current Source Rectifier on a High Step-Up Push–Pull Multiresonant Converter

This paper presents an analysis on the effect of a parasitic capacitance full-bridge class-D current source rectifier (FB-CDCSR) on a high step-up push–pull multiresonant converter (HSPPMRC). The proposed converter can provide high voltage for a 12 VDC battery using an isolated transformer and an FB-CDCSR. The main switches of the push–pull and diode full-bridge rectifier can be operated under a zero-current switching condition (ZCS). The advantages of this technique are that it uses a leakage inductance to achieve the ZCS for the power switch, and the leakage inductance and parasitic junction capacitance are used to design the secondary side of the resonant circuit. A prototype HSPPMRC was built and operated at 200 kHz fixed switching frequency, 340 VDC output voltage, and 250 W output power. In addition, the efficiency is equal to 96% at maximum load. Analysis of the effect of the parasitic junction capacitance on the full-bridge rectifier indicates that it has a significant impact on the operating point of the resonant tank and voltage. The proposed circuit design was verified via experimental results, which were found to be in agreement with the theoretical analysis.