Passive Clamp Circuit Research Articles

English

In this paper, to achieve high step-up voltage gain and high efficiency, a novel high step-up ratio using clamp-circuit in addition capacitor and diode along with the boost inductor is proposed. The capacitor gets charged during the switch-off period and discharged during the switch-on period by the energy stored in the inductor which leads to high voltage gain. The leakage-inductor energy of the coupled inductor is recycled with a passive clamp circuit. Thus, the voltage stress on the main switch is reduced. The switch with low resistance RDS is used to reduce the conduction loss which increases the efficiency. The operating principle and steady-state analyses are discussed in detail. Finally, a prototype circuit with 24-V input voltage, 48-V output voltage, is implemented in the laboratory to verify the performance of the proposed converter.

A Family of Multilevel Passive Clamp Circuits With Coupled Inductor Suitable for Single-Phase Isolated Full-Bridge Boost PFC Converter

A family of multilevel passive clamp circuits is proposed and investigated in a single-phase isolated full-bridge boost power factor correction (PFC) converter, by which the voltage spike across primary side of the power transformer can be suppressed effectively, and the absorbed energy can be transferred to the output side automatically. These clamp circuits are composed of several capacitors, diodes and one coupled inductor. With the help of the coupled inductor, synchronous resonances of the different resonant circuits can be achieved, which will avoid the unbalance of the voltage and current in these circuits. For the N-level passive clamp circuit, as N increases, the maximum duty cycle of the PFC converter will increase, the current stress of the switches will decrease, and the volume of the coupled inductor will decrease. Take a three-level clamp circuit for example, the operational principle of multilevel clamp circuits are discussed. Furthermore, some related analysis and comparison are given. Finally, experimental study has been done on a laboratory-made single-phase PFC prototype in which a four-level and a five-level clamp circuits are adopted, respectively. The feasibility of the proposed method and the validity of the theoretical analysis are verified by the experimental results.

High step‐up passive absorption circuit used in non‐isolated high step‐up converter

To obtain a high step-up gain with high efficiency in distributed power sources application, such as photovoltaic (PV) and fuel cells, a passive absorption circuit with voltage step-up character is inserted in the interleaved flyback-forward converter for leakage energy recycle and voltage gain extension. By applying the high step-up passive-clamp circuit, the voltage spike on the metal-oxide semiconductor field-effect transistor is clamped and the energy stored inside the leakage inductance of the coupled inductor can be recycled to get high-output voltage. Moreover, it offers another design freedom to obtain higher voltage-conversion ratio. The operational principle and characteristics of the improved flyback-forward converter are presented, and verified experimentally with a 500 W prototype converter. The proposed high step-up passive-clamp can be widely used in high step-up DC-DC converter applications, and a new high step-up topology is deduced to illustrate the theoretical analysis.

High step-up isolated efficient single switch DC-DC converter for renewable energy source

In this paper, an isolated high step-up single switch DC-DC converter for renewable energy source is proposed. In the proposed converter high step-up voltage is obtained by single power switching technique that operates low duty cycle with isolated transformer inductors and switched capacitors and power diodes. The disadvantage of conventional converters is that it has high duty ratio and high voltage stress on power devices with less efficiency. The proposed converter eliminates the switching losses and recycles the leakage energy which includes reverse recovery energy of the power diode by using passive clamp circuit. To achieve high output voltage gain, the isolated transformer primary terminal and secondary terminal are connected in series during switching operation. PSIM software has been used for simulation. Simulation circuit is analyzed at 40Vdc/400Vdc, 200W and this operation is validated by implementing in the hardware model at 12Vdc/120Vdc, 60W.

Lossless passive snubber for double ended flyback converter with passive clamp circuit

Transformer leakage inductance in flyback converter results in high switch losses and stresses. For practical implementation of this converter snubber and clamp circuits are necessary. In this study a new passive lossless snubber and clamp circuit for double ended flyback converter is introduced. Operation of the new snubber is independent of load, and the converter duty cycle can be changed in a wide range. The proposed converter is analysed and experimental results are presented to justify the theoretical analysis.

High-Conversion-Ratio Bidirectional DC–DC Converter With Coupled Inductor

In this paper, a high-conversion-ratio bidirectional dc-dc converter with coupled inductor is proposed. In the boost mode, two capacitors are parallel charged and series discharged by the coupled inductor. Thus, high step-up voltage gain can be achieved with an appropriate duty ratio. The voltage stress on the main switch is reduced by a passive clamp circuit. Therefore, the low resistance RDS(ON) of the main switch can be adopted to reduce conduction loss. In the buck mode, two capacitors are series charged and parallel discharged by the coupled inductor. The bidirectional converter can have high step-down gain. Aside from that, all of the switches achieve zero voltage-switching turn-on, and the switching loss can be improved. Due to two active clamp circuits, the energy of the leakage inductor of the coupled inductor is recycled. The efficiency can be further improved. The operating principle and the steady-state analyses of the voltage gain are discussed. Finally, a 24-V-input-voltage, 400-V-output-voltage, and 200-W-output-power prototype circuit is implemented in the laboratory to verify the performance.

High Step-Up DC-DC Converter for Distributed Generation System

This study proposes a method which consists of High step up DC-DC converter with a coupled inductor for distributed generation system. Theoretically the conventional boost converter provides high step up voltage gain but in practical it is limited by reverse recovery problem of diode, effective series impedance of inductors and capacitors and switching losses. High charged current and conduction losses occur in the switch when voltage lift and switched capacitor techniques are used. In the proposed strategy a coupled-inductor and two capacitors is utilized to achieve high step-up voltage gain. High power loss and voltage spike on the switch is avoided using passive clamp circuit that recycles the leakage inductor energy. The operating principle and steady-state analysis are discussed. The Proposed topology was simulated using PSPICE SOFTWARE and the following results were obtained. For an input voltage of 24V, an output of 333V was obtained.

Novel High Step-Up DC–DC Converter for Distributed Generation System

In this paper, a novel high step-up dc–dc converter for distributed generation systems is proposed. The concept is to utilize two capacitors and one coupled inductor. The two capacitors are charged in parallel during the switch-off period and are discharged in series during the switch-on period by the energy stored in the coupled inductor to achieve a high step-up voltage gain. In addition, the leakage-inductor energy of the coupled inductor is recycled with a passive clamp circuit. Thus, the voltage stress on the main switch is reduced. The switch with low resistance <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$R_{\rm DS(ON)}$</tex></formula> can be adopted to reduce the conduction loss. In addition, the reverse-recovery problem of the diodes is alleviated, and thus, the efficiency can be further improved. The operating principle and steady-state analyses are discussed in detail. Finally, a prototype circuit with 24-V input voltage, 400-V output voltage, and 200-W output power is implemented in the laboratory to verify the performance of the proposed converter.

A High Step-Down Interleaved Buck Converter with Active-Clamp Circuits for Wind Turbines

In this paper, a high step-down interleaved buck coupled-inductor converter (IBCC) with active-clamp circuits for wind energy conversion has been studied. In high step-down voltage applications, an IBCC can extend duty ratio and reduce voltage stresses on active switches. In order to reduce switching losses of active switches to improve conversion efficiency, a IBCC with soft-switching techniques is usually required. Compared with passive-clamp circuits, the IBCC with active-clamp circuits have lower switching losses and minimum ringing voltage of the active switches. Thus, the proposed IBCC with active-clamp circuits for wind energy conversion can significantly increase conversion efficiency. Finally, a 240 W prototype of the proposed IBCC with active-clamp circuits was built and implemented. Experimental results have shown that efficiency can reach as high as 91%. The proposed IBCC with active-clamp circuits is presented in high step-down voltage applications to verify the performance and the feasibility for energy conversion of wind turbines.

Novel High Step-Up DC–DC Converter With Coupled-Inductor and Switched-Capacitor Techniques for a Sustainable Energy System

In this paper, a novel high step-up dc–dc converter is proposed for a sustainable energy system. The proposed converter uses coupled-inductor and switched-capacitor techniques. The capacitors are charged in parallel and discharged in series by the coupled inductor to achieve high step-up voltage gain with an appropriate duty ratio. Besides, the voltage stress on the main switch is reduced with a passive clamp circuit; low on-state resistance R <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$_{\bf {ds(on)}}$</tex></formula> of the main switch can be adopted to reduce the conduction loss. In addition, the reverse-recovery problem of the diode is alleviated by a coupled inductor. Thus, the efficiency can be further improved. The operating principle and steady-state analyses of voltage gain are discussed in detail. Finally, a prototype circuit with 24-V input voltage, 400-V output voltage, and 200-W output power is implemented in the laboratory to verify the performance of the proposed converter.

A Novel High Step-Up DC–DC Converter for a Microgrid System

A novel high step-up dc-dc converter for a distributed generation system is proposed in this paper. The concept is composed of two capacitors, two diodes, and one coupled inductor. Two capacitors are charged in parallel, and are discharged in series by the coupled inductor. Thus, high step-up voltage gain can be achieved with an appropriate duty ratio. The voltage stresses on the main switch and output diode are reduced by a passive clamp circuit. Therefore, low resistance R for the main switch can be adopted to reduce conduction loss. In addition, the reverse-recovery problem of the diode is alleviated, and thus, the efficiency can be further improved. The operating principle and steady-state analyses of the voltage gain are also discussed in detail. Finally, a 24-V input voltage, 400-V output voltage, and 400-W output power prototype circuit of the proposed converter are implemented in the laboratory to verify the performance.