相较于传统车载充电系统,集成型车载充电系统(integrated onboard charger system,IOCS)在成本、功率密度等方面具备显著优势.文中基于六相永磁电驱系统设计了一台IOCS,并研究了模型预测电流控制(model predictive current control,MPCC)算法在该系统并网模式下的应用.首先,分析所提IOCS的电路拓扑并建立数学模型,同时介绍传统MPCC的实施流程.然后,针对传统MPCC计算量大、稳态性能差等不足,提出一种基于占空比优化的MPCC(MPCC based on duty cycle optimization,DCO-MPCC)策略.一方面,减少备选电压矢量数量,降低电流预测环节带来的计算负担;另一方面,提出一种占空比优化技术,改善系统稳态性能.最后,通过实验验证了所提算法的有效性与优越性.实验结果表明,DCO-MPCC策略能够显著提升系统稳态性能并减少算法计算量.充电与车网互动(vehicle to grid,V2G)工况下,网侧电流总谐波畸变(total harmonic distortion,THD)分别降低6.18％与5.92％,算法运行时间减少17.54μs.
Model predictive control strategy for grid-connected operation of integrated onboard charger system
Comparing to traditional onboard chargers,integrated onboard charger system(IOCS)takes obvious merits in terms of cost and power density.In this paper,an IOCS based on a six-phase permanent magnet motor drive is designed,and model predictive current control(MPCC)methods are studied for the IOCS under the grid-connection modes.At first,the topology of the IOCS is analyzed and the mathematical model is established.Following this,the implementation of traditional MPCC is also introduced.Then,a MPCC based on duty cycle optimization(DCO-MPCC)is proposed to overcome the disadvantages of the traditional MPCC including high computation burden and bad steady-state performance.On the one hand,the computation burden is alleviated by reducing the number of the alternative voltage vectors.On the other hand,a duty cycle optimization technique is proposed to enhance the steady-state performance.Finally,the effectiveness and superiority of the proposed control strategy are verified using experiments.The experimental results indicate that the proposed control strategy can significantly enhance the steady-state performance of the system and reduce the computation burden.The total harmonic distortion(THD)of grid current is reduced by 6.18％and 5.92％under charging and vehicle to grid(V2G)operations,respectively.Meanwhile,the execution time of the proposed strategy is decreased by 17.54 μs.
integrated onboard charger system(IOCS)six-phase permanent magnet motormodel predictive current control(MPCC)alternative voltage vectorsduty cycle optimization(DCO)vehicle to grid(V2G)
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维普
