Design and performance analysis of Cockroft-Walton Voltage Multiplier (CWVM) energy harvesting for low power applications

Abstract

In this paper, the performance analysis of Cockroft-Walton Voltage Multiplier (CWVM) and effect of employing the cascaded CWG stages has been analyzed for energy harvesting applications. In this proposed model, square wave has been employed as an input to Cockroft-Walton Voltage Multiplier for analyzing the performance of CWG. In this proposed system, the Cockroft-Walton Voltage Multiplier is fed with both low and high frequencies in the range of Hz to MHz keeping V in as 1V and appertaining 5 stage Cockroft-Walton Voltage Multiplier network and yielding different V out . In this demonstrative work, square wave of different frequencies — 10 Hz, 100 Hz, 1kHz, 10 kHz, 100 kHz, 1MHz, 2 MHz, 3 MHz, 4 MHz, 5 MHz and 10 MHz respectively, are applied as input to Cockroft-Walton voltage multiplier and corresponding output voltages are recorded and analyzed. The maximum output voltage obtained voltage for 10 kHz is 16.45 V at fourth stage of CWVM for all stages that make it more appealing for devices like humidity sensor devices, dimming fluorescent ballasts, dimming LED drivers. It has been observed that for frequencies below 10 kHz, the output falls on employing more than 5 CWGA stages whereas when the Cockroft-Walton Voltage Multiplier operates at frequencies more than 10 kHz, the output voltage increase with increase in number of stages of multiplier. The Schottky diode has been employed over crystal diodes to enhance the output efficiency of multiplier circuit because it has less dropout voltage drop than crystal diodes. A single stage CWG has been tested by feeding different input waveforms — square, triangular and sine wave and it has been concluded that the output voltage of CWG is maximum for square input and minimum for sine wave because square wave resting at peak values for maximum time provided sufficient time for capacitors in CWG to charge to maximum values. It has been concluded that the output voltage of a Cockroft-Walton Voltage Multiplier is a complete function of input signal frequency and input waveform shape. A hardware prototype of the proposed Cockroft-Walton Voltage Multiplier has been developed to validate the analytical results.