Efficient Methods of Harvesting Energy From Ultra-Short Duration Shock Loading

Harvesting energy from high-shock pulse events such as those experienced during high velocity impact and firing setback acceleration in munitions using piezoelectric-based harvesters and converting it to usable electrical energy is not new. However, efficient collection of the generated charges and its transfer to an electrical storage device such as a capacitor for pulse events with very short duration, such as those that last a small fraction of a millisecond such as 50–100 microseconds is challenging. Another challenge for such piezoelectric-based harvesters is their hardening to survive high levels of shock loading, sometimes in excess of 100–200,000 Gs. In this paper, the basic design and operation of two such piezoelectric-based energy harvesters and their charge collection and storage electronics are described. The novel methods described are shown to achieve this goal with very high efficiency. The paper also describes the development of test-beds to simulate electrical charge generation of the energy harvesting power sources during high velocity impact and munitions firing for use in the design and evaluation of the developed charge collection and storage electronics.