Push-pull Forward Converter Research Articles

Push-pull forward LLC resonant converter for low input voltage applications

A push-pull forward LLC resonant converter suitable for renewable energy power generation systems is proposed in this paper. The converter introduces the LLC resonant tank into the traditional push-pull forward converter and adopts pulse frequency modulation (PFM) control, which solves the problem of voltage spike of switches of the conventional push-pull converter, realizes the zero-voltage switching (ZVS) of the switches and has high conversion efficiency. In addition, the rectifier part of the structure adopts voltage doubling rectifier technology, which is beneficial to reduce the turn ratio and optimize the leakage inductance of the transformer. In this paper, the working principle of the converter is described in detail, and its gain characteristics and soft switching conditions are analyzed. Finally, an experimental prototype of 1 kW is built, and the output voltage of 380 V is achieved when the rated input voltage is 48–72 V, and its efficiency is up to 96.1 %.

A Novel Zero-Voltage-Switching Push-Pull Forward Converter with a Parallel Resonant Network

A novel zero-voltage-switching (ZVS) push-pull forward converter with a parallel resonant network is presented in this paper. The novel topology can provide a releasing loop for the energy storage in a leakage inductor for the duration of the power switching by the resonant capacitors paralleled with the primary windings of the transformer. Then the transformer leakage inductor is utilized to be resonant with the parallel capacitor, and the ZVS operation is achieved. This converter exhibits many advantages such as lower duty-cycle losses, limited peak voltage across the rectifier diodes and a higher efficiency. Furthermore, the operating principles and key problems of the converter design are analyzed in detail, and the ZVS conditions are derived. A 500W experimental converter prototype has been built to verify the effectiveness of the proposed converter, and its maximum efficiency reaches 94.8%.

A Highly Efficient and Reliable Power Scheme Using Improved Push-Pull Forward Converter for Heavy-Duty Train Applications

Electronically controlled pneumatic (ECP) brake systems have become popular in heavy-duty train applications because of their advantages, which include shorter stopping distances, improved handling, and less brake-shoe and wheel wear. In ECP brake systems, an improved power supply is required to support efficient and reliable operations. In this paper, we propose a new power converter for ECP brake systems, which is derived from a conventional push-pull converter. As opposed to conventional push-pull converters, we insert a clamping capacitor into the proposed circuit. This clamping capacitor simultaneously enables a greater number of operation modes for the proposed converter and absorbs the voltage spikes in the switch. The proposed converter is more suited for ECP brake applications that require high power, low voltage ripple, and high impedance. We theoretically analyze the proposed converter, and present the design guidelines. Further, we discuss the modeling and control aspects. We demonstrate the operations of the proposed model by performing both simulations and experiments.

Partial Power Conversion Device Without Large Electrolytic Capacitors for Power Flow Control and Voltage Compensation

A novel partial power conversion device (PPCD) is proposed to realize power flow control and voltage compensation in a three-phase power distribution system in this paper. The PPCD circuit, which is derived from the conventional push-pull forward converter, can achieve arbitrary voltage output without any large electrolytic capacitors. Thus, the system reliability can be enhanced. Furthermore, the converter has no full-rated components, which reduces the cost. In this paper, an injection model for power flow control is derived. A minimum power transfer control strategy is proposed to minimize the power losses during the operation. A closed-loop control method employing the synchronous reference frame theory for voltage compensation is also developed to enable the precise control. The systems with PPCD are simulated by MATLAB/Simulink to verify the functions. The experiments for voltage compensation are carried out based on a 30-kW prototype, which shows the effectiveness.

Single Stage Push-Pull Forward Inverter of PV Power Source

This paper proposed a single stage inverter for PhotoVoltaic(PV). The inverter is a push-pull forward converter employed synchronous rectifier technique. The push-pull forward converter is used to convert the photovoltaic battery output voltage into high frequency SPWM square wave, and the rectifier circuit is used to change the polarity of the isolation high frequency transformer output SPWM wave. For improve performance of the inverter in both the command tracking and the load disturbance regulation, a PID control strategy is realized by using the TMS320LF28335 DSP. Theoretical analysis and experimental results indicate that the proposed topology and control scheme are promising for the applications of PV power supply.

Double-Loop Push-Pull Forward DC/DC Converter Control System

With the continuous development of aviation technology, reliability requirements for air power is growing. As an important component, air static inverter air power has been studied extensively. In this paper, we study the following about the design of the front push-pull forward converter of Aeronautical Static Inverter: First, we design the Push-Pull Forward DC/DC converter control system on the basis of small-signal modeling; Secondly set control system parameters ; Finally, Through the simulation in MATLAB Simulink, we verify the design of the converter control parameter is reasonable, and then verify that Double-loop push-pull Forward DC/DC converter control system in the aviation static inverter is effectiveness.

Design of 48 V Voltage regulator modules with a novel integrated magnetics

The push-pull forward topology with the current-doubler and synchronous rectifier is a suitable approach for high-input voltage regulator modules (VRMs) used to supply high-performance microprocessors. In order to improve efficiency and reduce size, this paper proposes an improved push-pull forward converter with a novel integrated magnetics. All the magnetic components including input filter inductor, step-down transformer and output filter inductors are integrated into a single EI or EE core. This topology is essentially the modified push-pull converter with the built-in input filter and the coupled-inductor current doubler rectifier. The proposed integrated magnetic structure features a simple core structure, a small leakage inductance and low winding and core losses. A design is given for a 48-V VRM with a 1.2-V and 70-A output, and its experimental results show that the proposed approach can offer a great improvement in efficiency.