In recent years, DC-DC converters find many applications in low to medium power range. The isolated converters are used in medium power application such as military, electric vehicle (EV) and space industries since they provide isolation between input and output and protection from input side faults. These are made capable of providing a specified output voltage by managing the PWM pulses delivered to the switching device\'s gate. This paper presents use of voltage feed-forward method which helps in suppressing effect of input line harmonics and disturbances and gives regulated output voltage. The converter is operating at a switching frequency of 140 kHz and behaviour of switching device is not taken into consideration. The converter has protection circuits like over voltage protection (OVP), over current protection (OCP) on input and outputs, under voltage protection (UVP) which protects from abnormal operating condition. The design and simulation results of the feed-forward technique with type-2 compensation and protection circuits are discussed.
Switch mode power supplies have been used in applications where high efficiency and better reliability is of prime concern. The dc-dc converter often categorised into isolated and non-isolated. In isolated dc-dc converter forward topology is preferred when output power demand is in the range of 150-200W . Though isolated dc-dc converters provide galvanic isolation between input and output, there are instances where it’s required to provide protection against short circuit or over load current, output over voltage and input under voltages and these may be drawback for the converter operation. Hence this paper explains a very effective techniques to overcome these drawbacks. The voltage feed-forward method with type-2 compensation is explained as it does not depend on load variation; instead, it reacts to control signals that have been predefined. It is used to lessen the abrupt changes in the input line voltage fluctuations cause changes in output voltage, which provides improved regulation by adjusting the duty cycle in accordance with change in input voltage . The other protection circuits like over current, over voltage and under voltage are simulated and results of the same are presented. The simulation is carried out using LTspice software.
II. VOLATGE FEED-FORWARD METHOD WITH TYPE-2 COMPENSATION
To have a stable closed loop converter with appropriate performance, a properly designed compensator is required. Hence type-2 compensation with voltage feed-forward method is used, which gives fast dynamic response against the input voltage variations. The following parameters are considered to design type-2 compensation.
Authors are thankful to the Management, Principal and Vice Principal, Dayananda Sagar College of Engineering and Centum Electronics Ltd. for their continuous support.
The voltage feed-forward method helps in achieving fast dynamic response of output voltage against input voltage variations. Apart from this, protection circuits also play vital role in the safe operation of the converter as it protects from over voltage or current damage. Hence it’s necessary to deign protection circuit for better reliability and effective working of the converter.
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