ISSN (Print) : 2320 – 3765 ISSN (Online): 2278 – 8875 International Journal of Advanced Research in Electrical, Electronics and Instrumentation Engineering (An ISO 3297: 2007 Certified Organization) Vol. 5, I ssue 5, May 2016 Copyright to IJAREEIE DOI:10.15662/IJAREEIE.2016.0505104 4329 Generation of HVDC from Voltage Multiplier Using Marx Generator Dwarakanath S.K 1 , Prateek Raj 2 , Praveen K.S 3 , Saurabh 4 , Shwetha 5 Asst. Professor, Dept. of EEE, SJBIT, Bangalore, Karnataka, India 1 UG Student, Dept. of EEE, SJBIT, Bangalore, Karnataka, India 2,3,4,5 ABSTRACT: The Marx Principle was developed by Erwin Otto Marx. Its principle is to generate a high voltage pulse using a number of capacitors in parallel to charge up during the on time and then connected in series to develop higher voltage during the off period. This principle is used to generate voltages in the range of KV’s in real-time for testing the insulation of the electronic appliances like transformers and the insulation of the power carryinglines. This project consists of 4 stages and each stage is made of one MOSFET, two diodes, and one capacitor. MOSFET is used as a switch; diodes are used to charge the capacitor at each stage without power loss. A 555 timer generates pulses for the capacitors to charge in parallel during ON time. During OFF time of the pulses the capacitors are brought in series with the help of MOSFET switches. Finally, number of capacitors used in series (4 in our project) adds up the voltage to approximately 3 (4 capacitors-1 capacitor) times the supply voltage. This system structure gives compactness and easiness to implement the total system. I. INTRODUCTION With the development of solid-state electronics, solid-state devices are becoming more and more suitable for pulsed power application. They could provide the pulsed power systems with compactness, reliability, high repetition rate, and long life time. The rising of pulsed power generators using solid-state devices eliminates limitations of conventional components, and promises pulsed power technology to be widely used in commercial applications. However, solid-state switching devices such as MOSFET available now are only rated up to a few kilo Volts. Most of pulsed power systems demand much higher voltage ratings. II. DEVELOPMENT OF MARX GENERATOR Conventional Marx Generator The generator capacitance C is to be first charged and then discharged into the wave shaping circuits. A single capacitor C may be used for voltages up to 200 kV. For producing very high voltages, a bank of capacitor are charged in parallel and then discharged in series. The arrangement for charging the capacitors in parallel and then connecting them in series for discharging was originally proposed by Erwin Otto Marx in 1923 as shown in Fig.1. Usually the charging resistance is chosen to limit the charging current to about 50 to 100 mA, and the generator capacitance C is chosen such that the product CRs is about 10s to 1 min. The gap spacing is chosen such that the breakdown voltage of the gap G is greater than the charging voltage V. Thus, all the capacitances are charged to the voltage V in about 1 minute. When the impulse generator is to be discharged, the gaps G are made to spark over simultaneously by some external means. Thus, all the capacitors C get connected in series and discharge into the load capacitance or the test object. The discharge time constant CR1/n (for n stages) willbe very small compared to charging time constant CRs which will be few be very small be very small compared to charging time constant CRs which will be few seconds. Fig.1: Conventional Marx Generator