Research On The Optimized PWM Control Strategy Of Three-phase Invertor

At present, while most countries around the world are competing for development of the green renewable sources of energy, solar energy is accepted commonly because of its unusual advantages, and inverters have played an important role in almost all of new renewable energy generation systems. Pulse-width modulation is the main control strategy of inverters in all the control strategies. It is a technical problem to select the optimal pulse width control strategy based on different performance indicators. Theoretical and simulation studies and experimental analysis are done for the performance indicators of various control strategies.In refer to the related literature at home and abroad, principle and harmonic characteristics of traditional sinusoidal PWM (SPWM) is analyzed in detail at the first part of this paper, and simulation and comparison of its four realization method is done, the result indicates the symmetrical regular sampling method is most superior. This paper introduces the principle and concrete realization method of space voltage vector PWM (SVPWM) control technology which is widely used in recent years for the low DC voltage utilization of SPWM, and from the switch succession, time of various voltages vector, as well as in the modulation wave function and the wave, these four aspects have proven SVPWM and rules sampling SPWM of sine modulation wave entering of zero-sequence component uz are completely consistent.A simplified SVPWM method is studied to reduce the amount of calculation algorithm for complex effect time of sector vector of SVPWM. According to the shortcomings of SPWM and quasi-optimizing SVPWM in terms of reducing switching losses, the most optimize zero vector SVPWM modulation strategy is come forward based on the studies on several specific optimization measures.On the basis of previous work, conventional SPWM, quasi-optimizing SVPWM, single-zero vector SVPWM, double-zero vector SVPWM and optimal zero vector SVPWM are studied and compared from the aspects of improving the utilization rate of voltage and current and voltage harmonic analysis, and the difference and relationship between them are pointed out. Two kinds of simple and easy to implement algorithm are put forward for the complex algorithm of optimal zero vector SVPWM, and simulation and experimental verify their feasibility. Theoretical analysis and simulation results show that:if low voltage and current harmonics, low ripple torque, are the performance indicators to pursue, then quasi-optimizing SVPWM is first choice; if low switch loss is the performance indicator to pursue, then optimal zero vector SVPWM is the most ideal control strategy.Finally, implementation methods of optimal control strategies on TMS320F2812DSP are introduced, and the experimental results are analyzed.