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Current Reversal in Inductive Loads

IP.com Disclosure Number: IPCOM000090311D
Original Publication Date: 1969-Mar-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Froess, RJ: AUTHOR

Abstract

The circuit effects rapid current reversal in an inductive load L with provisions for load current sensing. Load current IL is reversed by increasing the input voltage at point 1 to turn T2 on and T1 off. Therefore, load voltage VL decreases to -E as I2 and IL both discharge capacitor C. As IL continues to discharge C, a reverse bias on D2 occurs allowing VL to become more negative than supply voltage -E. A conventional amplifier, without diodes D1 and D2, prevents VL from passing -E by clamping it at the supply voltage. By proper selection of L, C, and R, a low-loss resonant circuit is formed. This now oscillates for one half a cycle during which IL is reversed. When VL again becomes more positive than tE, diode D2 is forward biased and any current losses are replenished by T2 during period T2.

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Current Reversal in Inductive Loads

The circuit effects rapid current reversal in an inductive load L with provisions for load current sensing. Load current IL is reversed by increasing the input voltage at point 1 to turn T2 on and T1 off. Therefore, load voltage VL decreases to -E as I2 and IL both discharge capacitor C. As IL continues to discharge C, a reverse bias on D2 occurs allowing VL to become more negative than supply voltage -E. A conventional amplifier, without diodes D1 and D2, prevents VL from passing -E by clamping it at the supply voltage. By proper selection of L, C, and R, a low-loss resonant circuit is formed. This now oscillates for one half a cycle during which IL is reversed. When VL again becomes more positive than tE, diode D2 is forward biased and any current losses are replenished by T2 during period T2. An initially negative IL can be similarly reversed as diode D2 allows VL to exceed the +E supply voltage.

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