Design and development of high frequency 360Watt RCD clamp forward converter for radar applications

Abstract

This paper deals with design and development of high frequency, high power Resister, Capacitor and Diode (RCD) clamp forward converter for Radar application. RCD clamp reset technique is used to reset the energy stored in the transformer during turn off. It is less expensive than using a tertiary winding, and as it allows duty cycle excursions above 50% and it greatly improves the behaviour in half-cycle dropout tests. The Converter is operating at a fixed frequency of 350 KHz with current mode control technique. Two transformer approaches is used to reduce the power loss and to increase efficiency. The UCC28C43 current mode controller is used as PWM controller to drive the switching MOSFET. The Optocoupler is used in the feedback control circuit for the purpose of isolation and hence it reduces the circuit complexity. This paper also deals with the specifications, design challenges and design procedure. Prototype model is developed and is tested to deliver the regulated output of 12V/30A with 270V input DC bus with efficiency 80%.

Design Oriented Analysis of the RCD Voltage Clamp Circuit for the Forward Converter

“…The sum of voltages V is given by 13 1 2 Substituting (7) in ( 6) we find To simplify the analysis and because the continuous component of the current is much smaller than its peak value, we assume that all of the energy is absorbed by the capacitor. The electrical charge transferred to the capacitor during the time intervals 1 t  and 2 t  is given by…”

In‐depth analysis of an RCD snubber applied to a DC‐DC boost converter

“…An RCD clamp circuit associated with a 360‐W forward converter for radar applications is described in Lakshmi et al 15 This is a feasible solution because it is possible to reduce the voltage stress on the switch, as well as to provide the operation with duty ratios higher than 50% unlike resonant‐type snubbers. The performance comparison between the two‐switch and RCD clamp forward converters is described in 16 considering the same design and component specifications.…”

Zero‐current transition single‐ended forward converter

“…In [1][2][3], the resistor-capacitor-diode (RCD) clamp circuit consisting of a resistor, a capacitor, and a diode is applied in parallel with the transformer of SEFC to absorb the leakage inductor energy of the transformer when the power switch turns off. By using the RCD circuit, the reset of the transformer is achieved without the need to reset winding and thus the voltage stress across the switch is reduced.…”

“…However, (i) the tertiary reset winding, (ii) high‐voltage spikes across power switch and rectifier diode due to resonant between parasitic capacitors and transformer leakage inductance, (iii) hard switching, which cause losses and electromagnetic interference (EMI), and (iv) reversing the recovery problems of output diodes is the main drawback of this converter. To solve these problems, some techniques are proposed in [1–23].…”