1. A method for energy harvest optimization of a solar photovoltaic system, comprising the steps of: A. reading a respective string output voltage desired for each of at least one or more strings of micro-optimizers by a manager; B. tracking a maximum power point for a photovoltaic assembly by each of the micro-optimizers, such that the photovoltaic assembly can provide maximum power; C. detecting parameters of an input current or input voltage, and calculating acquired input power by each of the micro-optimizers; D. calculating acquired output power according to the input power by each of the micro-optimizers wherein for each string of micro-optimizers, the output power is calculated based on the following equation: 
 Po ( T ) =k*Pi ( T ) wherein Po(T) is the output power of each string of micro-optimizers, Pi(T) is the input power of each string of micro-optimizers, and k is a preset power conversion efficiency; E. transmitting their output power to the manager by all the micro-optimizers; F. putting data on the output power for each string into one set, based on numberings of the micro-optimizers by the manager; G. calculating a sum of the output power for each string of micro-optimizers by the manager; H. comparing the output power sum obtained at present detection time with the output power sum obtained at last detection time, and if the difference is not larger than a threshold, returning back to the step E, otherwise proceeding to step I; I. calculating a string output current desired for each string of micro-optimizers by the manager wherein the string output current desired for each string of micro-optimizers is calculated based on the following equation: 
 Im ( T ) =Pm ( T )/ Vc wherein Im(T) is the string output current desired for the string of micro-optimizers, Pm(T) is the sum of the output power for the string of micro-optimizers, and Vc is the string output voltage desired for the string of micro-optimizers; J. transmitting the desired string output current to the micro-optimizer corresponding to the photovoltaic assembly as a management command by the manager; K. receiving the management command, controlling its power conversion circuit for DC-DC conversion by the micro-optimizer, such that the string output current is as desired; and L. returning back to the step B, such that the method repeats in loop.