The Armstrong Phase Modulation(PM)and Double Amplitude Modulation(AM)vector composing PM both are vector composing style circuits in the course"Radio Frequency Circuits".

This paper presents a new multi-level technique for three-phase current rectifier(CSR) based on vector synthesis scheme.

N rectifier units are paralleled directly and modulated based on space vector synthesis technique.

In stator flux linkage estimator based on the flux amplitude and phase compensation,traditional direct torque control scheme of three-level inverter based on synthesizing voltage vectors,a new predictive control method was proposed to reduce the large torque ripple caused by discontinuity of the voltage vectors in a work period.

Aiming at excessive torque ripple shortcomings caused by direct torque control of synthesizing voltage vectors in the threelevel inverter,a kind of new predictive control method was proposed to determine reference voltage vectors of the inverter according to errors of the flux and torque.

In order to obtain high LIDT antireflective (AR) coatings on the nonlinear optical crystal LiB3O5(LBO), this dissertation focuses its main interests on the following four aspects: Firstly,frequency doubling and tripling AR coatings were designed on the LBO crystal using vector addition method.