Three-vector-based Model Predictive Control Of Pwm Rectifier Without Power Compensation Under Unbalanced Grid Condition

PWM rectifier is widely used in superconducting energy storage and unified power flow controller because of its unit power factor and bidirectional energy flow.Most of the control strategies of PWM rectifiers are designed based on the balanced power grid,but the real power grid voltage is unbalanced,which will cause some abnormal operation of the device,mainly manifested in the increase of harmonic current on the grid side and the increase of DC voltage fluctuation,which may damage the device in serious cases.It is valuable to study the control of PWM rectifier under unbalanced power grid.Firstly,the principle of compensating power reference under unbalanced power grid is introduced.In order to simplify the control structure of PWM rectifier under unbalanced power grid,a new definition of reactive power is introduced to make the reference of reactive power under unbalanced power grid and the reference of reactive power under balanced power grid unified to zero,thus eliminating the channel of reactive power compensation in traditional unbalanced control scheme.Secondly,after analyzing the vector duration of three-vector-based model predictive control,it is found that the vector duration is redundant.By calculating the specific synthetic vector duration,the synthetic voltage vector duration can be restored,which avoids using the single vector model prediction algorithm to assist,and reduces the computational burden of the algorithm.The correctness and effectiveness of the proposed scheme are verified by simulation.Finally,a 2kW PWM rectifier experimental platform is set up,and a comparative experimental study is carried out.The experimental results show that the proposed scheme can obtain a control effect that is basically consistent with the power compensation-based unbalanced grid PWM rectifier control scheme,but the system structure is simpler,the execution time is new reactive power...