Design and optimization of hydrogen cooled pulsed storage inductors for electromagnetic launchers

Abstract

A b s t r a c t C r y o r e s i s t i v e magnetic energy s t o r a g e systems t h a t can d e l i v e r Meg-Amp K i lo-Vol t 1 eve1 s o f p u l sed power f o r a s h o r t t i m e (200-1000 s) have i m p o r t a n t p o t e n t i a l a p p l i c a t i o n s i n space-based s t r a t e g i c defense systems. Hydrogen c o o l e d aluminum c r y o r e s i s t i v e c o i l s o p e r a t i n g a t frequencies > 1 H, a r e e f f i c i e n t and l i g h t weight (AE/M = 20-50 J/g).I n t h i s paper we r e p o r t on: t l y i n t o t h e l o a d o v e r a s h o r t t i m e (1-10 ms). The purpose o f t h i s paper i s t o r e l a t e t h e p e r i o d i c p u l s e shape r e q u i r e d f o r r a i l g u n s t o t h e I R losses.Hydrogen cooled h i g h p u r i t y aluminum i s proposed as t h e l o w l o s s conductor because o f t h e a v a i l a b l e l i q u i d hydrogen f u e l . should be l a r g e enough so t h a t t h e c u r r e n t does n o t drop a p p r e c i a b l y d u r i n g t h e discharge. F o r such a p p l i c a t i o n s , t h e r e i s a needThe c y c l e i s p e r i o d i c f o r r e p e t i t i v e f i r i n g o f p r o j e c t i l e s , as seen i n Fig. 2. Time, t I n d u c t o r e l e c t r i c c u r r e n t r e p r e s e n t i n g p e r i o d i c charge and discharge. The ohmic l o s s i n a c o i l i s d i v i d e d i n t o two p a r t s : t h e dc l o s s , Pdc, r e l a t e d t o t h e average c u r r e n t , Iav; and t h e ac l o s s , Pac. l o s s , Pt, i s e x a c t l y equal t o t h e sum o f Pa, and Pdc. Pa, i s c a l c u l a t e d b y summing t h e power l o s s due t o t h e fundamental and a l l F o u r i e r harmonics o f t h e f i e l d o r c u r r e n t p a t t e r n . D e t a i l e d a n a l y s i s o f power l o s s c a l c u l a t i o n a r e i n c l u d e d i n r e f e r e n c e (1). a n a l y s i s covers l o s s e s f o r c a b l e conductors o r m u l t il a y e r c o i l s where each c a b l e w i r e o r c o i l l a y e r t r i e s t o s h i e l d i t s e l f from ac L i e l d s . F i g u r e 3 shows how a dimensionless r e s i s t a n c e , t h e r a t i o o f l o s s e s due t o a c t u a l c u r r e n t d i s t r i b u i i o n t o t h e l o s s e s f o r u n i f o r m c u r r e n t d i s t r i b u t i o n vs. Imax and Imin f o r e i t h e r t h e c a b l e w i r e diameter o r t h e l a y e r thickness.The curves shown cover a 4 cm t h i c k aluminum conductor i n a s i n g l e l a y e r c o i l t h a t i s e i t h e r r e p l a c e d b y a transposed c a b l e conductor o f w i r e s i z e d o r m u l t i l a y e r conductors w i t h reduced t h i c k n e s s d. has s m a l l e r r e s i s t a n c e u n l e s s t h e c a b l e s i z e o r t h e The t o t a l power The As shown a non-cabled s i n g l e l a y e r c o i l l a y e r t h i c k n e s s i n a m u l t i l a y e r c o i l i s s m a l l e r t h a n t h e s k i n depth.The c i r c u i t shown i n Fig. 1 i l l u s t r a t e s t h e voltage or power amplification function of the series i n d u c t o r connected ...

Novel Switch Adaptive Control to Improve the Efficiency of Boost Converter in Photovoltaic Systems

“…Another approach of increasing the efficiency of boost converters is to reduce the losses by careful design of the passive components within the power converter [14] [15] [16] [17]. This is especially true for inductors in dc-dc converters where the designer can optimise the cross-sectional area of conductors and reduce core flux densities in order to reduce losses.…”