STUDY OF HIGH FREQUENCY RESONANT GATE DRIVER FOR ZERO VOLTAGE SWITCHED SYNCHRONOUS RECTIFIER BUCK CONVERTER (ZVS-SRBC) CIRCUIT

In this work, a new Synchronous Rectifier Buck Converter (SRBC) circuit is proposed that reduces low switching and conduction losses. Moreover, the Miller effect has also been reduced. The limitations of existing single-channel resonant gate driver (S-CRGD) is studied to determine the optimized parameter values in terms of duty cycle, dead time and resonant inductance. The findings result in designing the new SRBC circuit’s symmetrical dual-channel resonant gate drive (D-CRGD). The aim is to generate low switching and gate drive losses by operating in Zero Voltage Switching (ZVS) and lower on-state drain voltage conditions. It is found that the SRBC can operate effectively at 1 MHz compared to the conventional SRBC in solving the issues of dead time and effect of switching frequency. Experimental results are presented to validate the analysis of the proposed design procedure and to demonstrate the performance of the proposed approach. In addition, several gate drive control schemes such as Fixed Dead Time (FDT), Adaptive Gate Drive (AGD) and Predictive Gate Drive (PGD) have been simulated and the results show that FDT can operate SRBC correctly with shorter dead time and eventually reduce body diode conduction loss. Even though FDT is prone to cross-conduction effect, the design stage is simple. Apart from this, AGD and PGD control schemes have also shown high level of efficiency. However, AGD generates more losses which makes PGD preferable in achieving a highly efficient converter although there are advantages in FDT scheme

State-space Modelling and Digital Controller Design for DC-DC Converter

The recent development in digital technology offers better platform for easy implementation of advance control algorithm in power converter design making digital control a viable alternative to analogue counterpart. Controller design for power converters has been very challenging due to non-linear characteristics of power switches, the supply voltage variability, load current changes and circuit element variation. This paper presents dynamic averaged state-space modelling of non-ideal dc-dc boost converter with parasitic and digital controller design for boost converter using digital redesign and direct digital design methods. The system was simulated in Matlab/Simulink to investigate the dynamic performance of the two controllers’ transient response, control bandwidth and response to variable supply voltage. The results demonstrated fast transient and wide control bandwidth for tight voltage regulation of variable input voltage

Phase-Shifted Full-Bridge Zero Voltage Switching DC-DC Converter Design with MATLAB/Simulink Implementation

Design of phase-shifted full bridge zero voltage switching DC-DC converter has been very challenging due to circuit parasitic effect on the system dynamics. This paper presents steady-state analysis and iterative approach for the systemic design of phase-shifted full bridge DC-DC converter with improved dynamic performance and satisfactory operational requirement in terms of zero-voltage switching range, operating switching frequency and switching resonance. A 3 kW DC-DC converter is designed using the iterative design approach and the system dynamics performance was investigated in the MATLAB/Simulink environment. The converter zero-voltage switching simulation results were satisfactory with 90% efficiency under full load condition

Multi-input DC-AC Inverter for Hybrid Renewable Energy Power System

The objective of this paper is to design a multi-input dc-ac inverter integrated photovoltaic array, wind turbine and fuel cell in order to simplify the hybrid power system and reduce the cost.  The output power characteristics of the photovoltaic array, wind turbine and fuel cell are introduced. The operational principle and technical details of the proposed multi-input dc-ac inverter is then explained. The proposed inverter consists of a three input flyback dc-dc converter and a single phase full bridge dc-ac inverter. The control strategy for the proposed inverter to distribute the power reasonably to the sources and it achieved a priority of the new energy utilization is discussed. This multi-input dc-ac inverter is capable of being operated in five conditions and power delivered to the ac load can be either individually or simultaneously. First to third condition occurs when the power delivered from either renewable energy sources individually, fourth condition happens when power is demanded from two sources simultaneously, and finally when power are available from three sources simultaneously. The proposed inverter has been simulated by employing NI Multisim 12.0 circuit simulator

Fundamental Approach in Digital Circuit Design for 1-MHz Frequency PWM Gate Drive Application

This paper discusses the design of a digital programmable logic circuit to produce a 5 V - output square wave pulses for four high power MOSFET switches using a fixed PWM circuit. It will be applied to drive the synchronous rectifier buck converter(SRBC) circuit. The PWM signals with multiple fixed time delay of 15 ns, 232 ns, 284 ns and 955 ns are generated. The steps taken to analyze each propagation time delay of each logic gate used and its combination are carefully studied. A multiplexer is added at the output of the logic circuit to select and produce the desired output pulses of 20% duty ratio. The logic outputs are compared with the analog pulses and results match each other within 1% in difference

An Improved DC Circuit Breaker Topology Capable of Efficient Current Breaking and Regeneration

The DC power system, due to its convenience of conversion, integration, and use, is getting immense attention in the field of power transmission and distribution. It is superior to traditional AC systems in terms of efficiency, reliability, and control simplicity as well. A DC circuit breaker is one of the important elements of any DC power system. It is a sophisticated technology designed to break DC current only. The breaking of a DC current is always challenging compared to the breaking of an AC current, as DC current does not have natural zero crossing points like AC current has. Moreover, DC current breaking becomes more critical when the current is inductive as energy stored in the network inductance opposes instantaneous current breaking. Hence, this energy needs to be absorbed and dissipated as heat during the current breaking operation, which is exactly what is done in the traditional DC circuit breaker topologies. This paper introduces a new topology for DC circuit breakers with a mechanism to reuse this stored energy instead of dissipating it. The mechanism is analogous to regenerative braking in electric drive systems and can enhance the overall system efficiency. The proposed scheme was analyzed through rigorous computer simulation and was experimentally validated

Two-diode model for parameters extraction of photovoltaic module under temperature variation

This paper study the effect of redistributing the series resistance in the two-diode model of the PV module according to its physical components, considering the relation of each component to temperature variation. The proposed model divide the series resistance into two materials: metal and semiconductor, constructing the mathematical model for the overall model. The model is found to improve the accuracy in calculating the maximum power point with temperature variation, which contribute to the job of PV power converter designers and circuit simulator developers

Theoretical analysis of the series parasitic resistance in photovoltaic cell

An accurate estimation of the series resistance in the PV model is crucial to the prediction of the maximal output power of the PV module, especially under temperature variation. This Paper proposes a theoretical expression to calculate accurately the value of this resistance. The proposed expression comes from the physical nature of the various elements constructing this resistance, plus the reverse relation of the output power with cell temperature, utilizing manufacturer datasheet only. The proposed expression was tested against experimental measurements and previous work, showing a clear improvement in tracing the series resistance values under varying temperature