Model Predictive Control For A Hybrid VIENNA Rectifier

With the development of industry,the load of power grid becomes heavier and heavier,and the requirements for power quality are getting higher and higher.Power quality has become an unavoidable problem.Conventional three-phase diode uncontrolled rectifiers are commonly used in high-power applications,but they can cause harmonic pollution to the power grid.A hybrid VIENNA rectifier provides a new solution for high power rectification.For the hybrid circuit topology of hybrid VIENNA rectifiers,it is very important to study its control strategy.In this paper,the Finite Control Set Model Predictive Control(FCS-MPC)is introduced into the hybrid VIENNA rectifier,and the control set is optimized to solve the problem of Conventional FCS-MPC(Conventional FCS-MPC,C-FCS-MPC)computational load.Firstly,the working principle of the hybrid VIENNA rectifier is analyzed and the mathematical model is established.The conventional voltage oriented and current decoupling control algorithm is introduced into the hybrid VIENNA system,and the scheme of power distribution and implementation scheme of the control system are described in detail.Then,the FCS-MPC control strategy of the hybrid VIENNA rectifier is studied.The corresponding discrete mathematical model and switch state table are established for the two parts of the hybrid VEINNA rectifier.The cost function is established according to the control requirements,and the C-FCS-MPC integrated implementation scheme of the system is given.Aiming at the negative impact of excessive computation of C-FCS-MPC strategy,a simplified Finite Control Set Model Predictive Control strategy(S-FCS-MPC)based on control set division is proposed.The theoretical analysis of the proposed S-FCS-MPC scheme is carried out,and the feasibility and effectiveness of the scheme on the hybrid VIENNA rectifier are demonstrated.Finally,aiming at the neutral-point voltage fluctuation in the hybrid VIENNA rectifier system,the reason of the neutral-point voltage fluctuation is analyzed,and the solution based on S-FCS-MPC strategy is carried out.A hybrid VIENNA rectifier experimental prototype with TI's TMS320F2812 DSP as the core control chip was built.Experimental verifications of voltage directional current decoupling control,S-FCS-MPC strategy and neutral-point balance control algorithm for hybrid VIENNA rectifiers are presented.The experimental results prove the correctness and feasibility of the proposed control methods,and S-FCS-MPC has better dynamic control performance than the conventional method.