Frequency response based dynamic performance analysis of switched mode power amplifiers used in electromagnetic levitation systems

Abstract

PSPICE is a general-purpose analog and digital electronic circuit simulator. It is a powerful program that is used in IC and board-level design to check the integrity of circuit designs and to predict circuit behaviour. The DC electromagnetic levitation system (EMLS) critically deserves very fast response and the DC-DC switch mode power amplifiers used for such applications have important role to meet this demand. The coil current for the magnets used in EMLS needs to be precisely controlled to meet the attractive force demand and this calls for a fast DC to DC power amplifier that can be controlled in a closed loop fashion. The main objective of this paper is to compare the dynamic performances between these different power amplifiers so that an insight can be made about the selection of power amplifier where speed of response and bandwidth is the prime criterion. The effect of different parameters of chopper amplifier (input DC link voltage, duty cycle and switching frequency) and levitation system (resistance and inductance of magnet coil) on the dynamic responses of amplifiers also been observed both by time and frequency response analysis utilizing PSPICE. This will lead to an inference for the design and development of chopper amplifier and DC EMLS. Experimental results to show the difference in dynamic responses between selective power circuits have also been presented.

Linear Boundary of Current Closed-Loop Control of Two-Quadrant H-Half Bridge Converter in Excitation System

“…Therefore, the average output voltage of the converter U o in the entire switch cycle T s is the same as expressed by (2).…”

“…When the converter works in Zone A and Zone B, the average model of the converter can be expressed by (2) and ac exciter field current I AB by the differential equations (5). At this time, the ac exciter field current I AB can be controlled easily by changing the duty ratio D between 0 ~ 1.…”

“…The classic four quadrants H bridge topology circuit is applied in many situations including DC-AC/AC-DC power supply, DC-DC switching power supply, electromagnetic actuator, DC electromagnetic levitation system (EMLS), DC motor speed control, etc., because of its excellent performances in adjusting the magnitude and polarity of the output voltage and current. Then, based on the four-quadrant H bridge circuit topology, a kind of H-half Bridge DC-DC converter working in 1 st and 4 th quadrant was presented in literature [1,2]. As shown in Fig.…”