In this paper, a new non-isolated soft switched DC-DC converter with high step-down conversion ratio is proposed. The proposed converter consists of two switch cells that their inputs and outputs are cascaded. This converter provides ultra-high step-down conversion rati More
In this paper, a new non-isolated soft switched DC-DC converter with high step-down conversion ratio is proposed. The proposed converter consists of two switch cells that their inputs and outputs are cascaded. This converter provides ultra-high step-down conversion ratio and due to all semiconductor devices are soft switched, switching losses are reduced, also reverse recovery losses of diodes are reduced because of ZCS turn off condition. The duty cycle of proposed converter is much larger than step-down converter and therefore does not have the problems of the converter with a narrow duty cycle and since no auxiliary switch is used to achieve soft switching, the control circuit remains simple. In this paper, the convertor operating modes are discussed and to verify the performance of the converter a 50W prototype with 100 kHz switching frequency, 100V input and 16V output is built. The converter efficiency is measured and the peak efficiency is 94% also the conducted electromagnetic interference peak in the proposed converter is reduced by 6dBµv.
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Recent developments in renewable energy sources has created demands for high step-up and high efficiency DC-DC converters. This demands are fulfilled basically through the use of high frequency transformer to achieve the required and desired gain. Power electronics solu More
Recent developments in renewable energy sources has created demands for high step-up and high efficiency DC-DC converters. This demands are fulfilled basically through the use of high frequency transformer to achieve the required and desired gain. Power electronics solutions based on multi-converter structures provides economic methods for input and output power by combining a number of components. In this paper some of structures reviewed that have been proposed to achieve a high step-up converter and the advantages and disadvantages of these converters are discussed. The proposed converter is provided in order to reduce the voltage stress of high step-up converters based on coupled inductor and passive clamping circuit. The voltage stress of switches in the proposed converter is less than a simple boost converter also in this structure with using passive clamping circuit the oscillation of both sides of the switches is a little clamped and finally by using this technique it can achieve high gain by selecting the appropriate duty cycle. In this paper to review the principle of operation of the proposed converter theoretical analysis are provided and to verify the results of theoretical analysis of the proposed converter is given with its PSPICE simulation.
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A triple-buck converter with zero voltage transient is presented in this paper. The proposed structure is formed by three parallel buck converter to increase the reliability which is utilized three interleaved inductors for connecting the stages to reduce the losses cau More
A triple-buck converter with zero voltage transient is presented in this paper. The proposed structure is formed by three parallel buck converter to increase the reliability which is utilized three interleaved inductors for connecting the stages to reduce the losses caused by hard switching. The zero voltage transistor is also performed by resonance between the parasitic capacitance of the power switches and the equivalent inductor seen from each capacitor. The proposed circuit analysis has been performed in different operating modes. The proposed Buck converter is simulated in the Matlab/Simulink environment. The simulation results prove that the switching losses as well as the loss of diodes can be reduced by zero voltage switching of the power switches and designed high-performance converter. The simulation results show that the output reaches its final value of 40 V after 0.6 ms and the output voltage variations is 0.5 V the output ripple is achieved 1.25%.
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Non-isolated buck converters are well-known solutions for producing controllable DC voltage at medium and high-power levels. Meanwhile, synchronous converters have received a lot of attention due to the non-dependence of the voltage conversion ratio on the load and the More
Non-isolated buck converters are well-known solutions for producing controllable DC voltage at medium and high-power levels. Meanwhile, synchronous converters have received a lot of attention due to the non-dependence of the voltage conversion ratio on the load and the continuity of the inductor current. But the switching of these converters takes place at higher power levels at lower frequencies. For this reason, the switching circuit must work with a higher dead time. In this article, an analog application circuit design without the use of a microcontroller is presented for the switching of the synchronous buck converter, which, while ensuring that pulses are not sent to the keys at the same time, the amount of dead time can be It provides a setting that can be changed according to the voltage level and current of the circuit. After analyzing the conditions at the moment of switching on and off of the circuit, it was found that at the moment of switching off, a destructive transient current is applied to the keys, which this article solves this issue by using two fast SSR relays in the path of the input signal to the gate module. The driver suggests that it has been tested on a prototype device. This article also mentions the requirements of the switching circuit by analyzing the conditions of the moment when the circuit is turned on and off, so that the transient damaging current does not pass through the IGBT. The results of experimental tests on a 15 kW synchronous buck DC/DC converter with an output of 300 V 50 amps show that the well-designed switching circuit creates an adjustable dead time of up to 6 microseconds in the switching of this converter and the continuity conditions It has provided the inductor current both in no load and under load. Also, the proposed method has well removed the transients of the circuit turning on and off.
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In this paper, a new nonisolated bidirectional buck–boost dc–dc converter is introduced. The proposed converter can be operated under ZVS condition and fixed switching frequency regardless of the direction of power flow. To provide ZVS condition for switches More
In this paper, a new nonisolated bidirectional buck–boost dc–dc converter is introduced. The proposed converter can be operated under ZVS condition and fixed switching frequency regardless of the direction of power flow. To provide ZVS condition for switches a simple auxiliary circuit is used, that consists of an auxiliary inductor and a coupled winding to main inductor. Due to ZVS operation of switches, the reverse recovery problem of the body diode of the switches does not occur. Moreover, to provide soft switching any extra switch is not used in this converter, so its implementation and control is very simple. The experimental and simulation results of the proposed bidirectional converter are given to confirm the theoretical analysis.
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