An approach to calculate the output parameters of mechanical excited piezoelectric element is described.Through this approach

the analytical expression of output current

voltage

power for two type piezoelectric generators is derived

and also the analytical expression for the optimal power flow from these piezoelectric generators is derived.Some experiments validate the approach.By analyzing the expressions

some characteristics of the piezoelectric generator is obtained and also the effect of related parameters on the piezoelectric generator is obtained

all of which can be used as the basis for the generator design optimization.