Appropriate charge control of the storage capacitor in a piezoelectric energy harvesting device for discontinuous load operation

Mechanical energy generated by human activity may be converted to electrical energy using piezoelectric film inserts inside a shoe. This electrical energy can be collected in the form of charge accumulated in a storage capacitor. Under this scheme, the storage capacitor needs only to be connected to the load when it has enough energy for the requested operation. This time interval depends on several parameters: piezoelectric type and magnitude of excitation, required energy and voltage, and magnitude of the capacitor. This work analyzes these parameters to find an appropriate choice of storage capacitor and voltage intervals.