New Schemes Of Space Vector Pulse Width Modulation For Single-phase And Three-phase Inverters

Inverter is a kind of converter used to convert direct current to alternating current. Due to advantages such as low switching frequency and high utilization of DC voltage, Voltage Space Vector Pulse Width Modulation (SVPWM) is being widely applied to inverter control.Various schemes appliying SVPWM to diverse kinds of inverters are studied in this paper. On the basis of brief introduction to SVPWM scheme in traditional three-phase inverter, this paper focuses on implementation of SVPWM in inverter for one-phase, three-phase-four-leg inverter as well as three-level inverter.As for two-phase inverter, implementation schemes of SVPWM in two-phase three-leg inverter and two-phase four-leg inverter are put forward in this paper, which can not only ensure circular rotating magnetic field, but also omit starting and running capacitors used for displacement of phase currents. To verify effectiveness of the proposed scheme, simulations of two types of inverters are conductd by means of MATLAB/SIMULINK, after which advantages and disadvantages of them are analyzed. Moreover, a protoytpe is manufactured with DSP-TMS320LF2407A produced by TI company. Experimental results show that the proposed scheme accords with anticipated purpose and therefore, it can be widely applied to speed adjustment with variable voltage and variable frequency(VVVF) for single-phase motor.As for three-phase inverter, attention is paid on problems about implementation of SVPWM scheme in topological structure of three-phase-four-leg inverter under unbalanced load. Compared to other topologies of three-phase-four-wire inverters, three-phase-four-leg inverter can promise symmetrical three-phase ouput voltage under unbanlanced load. Scheme of Three Dimensional Space Vector Pulse Widith Modulation (3DSVPWM) used in this topology is discussed and specific scheme of 3DSVPWM is deduced. Simulative is conducted through MATLAB. In order to further verify feasibility, a protoytpe is made with TMS320F2812 produced by TI company and C language program is written. Excellent experimental results are obtained. With regards to Neutral Point Clamped Three-Level Inverter, its merits is realization of middle and high voltage converters with low voltage power device as well as sinusoidal voltage output, consequently, it is extensively used in applications of high voltage and high power capability. Based on detailed analysis about working principles of Neutral Point Clamped Three-Level Inverter, scheme of SVPWM in this inverter is discussed and corresponding switching sequence and calculation formula are given. Effectiveness of this scheme is verified through simulation with MATLAB.