By using the output inductors and body capacitances without adding any component compared with hard switching synchronous rectifier,the topology of a soft switched synchronous rectifier with phase-shifted full bridge ...By using the output inductors and body capacitances without adding any component compared with hard switching synchronous rectifier,the topology of a soft switched synchronous rectifier with phase-shifted full bridge zero voltage switching DC/DC converter is proposed. The converter efficiency is maximized due to soft switching of the full bridge MOSFETs and the synchronous MOSFETs, and also the low conduction loss of synchronous MOSFET. The operation principles of the circuit are analyzed in detail and the small-signal model is derived, also the converter dynamic characteristics are analyzed. Frequency responses of transfer functions under different values of transformer primary leakage inductance are discussed. The experimental results were obtained from a 400 V input and 100 A/12 V output DC/DC converter operating at 100 kHz. The results show that the converter efficiency is 2% higher in rated power than traditional diode rectifier.展开更多
The problem of controlling a single-input-single-output plant without prior knowledge of high frequency gain sign is addressed by using the model reference robust control approach.A switching method is proposed based ...The problem of controlling a single-input-single-output plant without prior knowledge of high frequency gain sign is addressed by using the model reference robust control approach.A switching method is proposed based on a monitoring function so that after a finite number of swi- tchings the tracking error converges to zero exponentially.Furthermore,it is shown that if some initial states of the closed-loop system are zero,only one switching is needed.展开更多
以三相Vienna整流器为研究对象,针对有限集模型预测控制FCS-MPC(finite control set model predictive control)实现中点电位平衡控制时权重因子选取困难,采样周期内作用单一矢量引起网侧电流纹波较大的问题,提出一种基于双矢量的无权...以三相Vienna整流器为研究对象,针对有限集模型预测控制FCS-MPC(finite control set model predictive control)实现中点电位平衡控制时权重因子选取困难,采样周期内作用单一矢量引起网侧电流纹波较大的问题,提出一种基于双矢量的无权重型模型预测控制UF-MPC(unweighted factor model predictive control)策略。首先,构建基于功率预测的单目标价值函数。然后,通过扇区划分同时采用无权重因子的方式来提高单次寻优效率,根据直流侧中点电位的波动优选冗余小矢量,实现无权重因子的中点电位平衡控制。在获取最优矢量的基础上,结合零矢量实现了双矢量固定开关频率控制。最后,基于RT-LAB半实物平台从稳态、暂态、中点电位波动方面进行验证,有效证明了所提控制策略的正确性和有效性。展开更多
文摘By using the output inductors and body capacitances without adding any component compared with hard switching synchronous rectifier,the topology of a soft switched synchronous rectifier with phase-shifted full bridge zero voltage switching DC/DC converter is proposed. The converter efficiency is maximized due to soft switching of the full bridge MOSFETs and the synchronous MOSFETs, and also the low conduction loss of synchronous MOSFET. The operation principles of the circuit are analyzed in detail and the small-signal model is derived, also the converter dynamic characteristics are analyzed. Frequency responses of transfer functions under different values of transformer primary leakage inductance are discussed. The experimental results were obtained from a 400 V input and 100 A/12 V output DC/DC converter operating at 100 kHz. The results show that the converter efficiency is 2% higher in rated power than traditional diode rectifier.
基金Supported by National Natural Science Foundation of P.R.China(60174001)National Natural Science Foundation of Beijing(4022007)
文摘The problem of controlling a single-input-single-output plant without prior knowledge of high frequency gain sign is addressed by using the model reference robust control approach.A switching method is proposed based on a monitoring function so that after a finite number of swi- tchings the tracking error converges to zero exponentially.Furthermore,it is shown that if some initial states of the closed-loop system are zero,only one switching is needed.
文摘针对低压输入的DC/DC变换应用,提出了一种定频脉冲宽度调制(pulse width modulation,PWM)的推挽正激谐振变换器。一次侧采用推挽正激结构,二次侧在谐振网络与倍压整流相结合的基础上引入两个有源开关,通过定频调节二次侧有源开关的占空比,变换器在一个开关周期内具备二倍压整流和四倍压整流两种模式,从而实现宽电压增益范围的调节。谐振网络的引入使一二次侧开关管均可实现零电压开通(zero voltage switch,ZVS)。在分析工作原理的基础上,利用时域分析法推导得到了变换器的增益与重叠导通角的关系,并分析了开关管软开关的实现条件。搭建了额定功率1kW的实验样机,实验结果证明了原理分析的正确性与拓扑方案的可行性。
文摘以三相Vienna整流器为研究对象,针对有限集模型预测控制FCS-MPC(finite control set model predictive control)实现中点电位平衡控制时权重因子选取困难,采样周期内作用单一矢量引起网侧电流纹波较大的问题,提出一种基于双矢量的无权重型模型预测控制UF-MPC(unweighted factor model predictive control)策略。首先,构建基于功率预测的单目标价值函数。然后,通过扇区划分同时采用无权重因子的方式来提高单次寻优效率,根据直流侧中点电位的波动优选冗余小矢量,实现无权重因子的中点电位平衡控制。在获取最优矢量的基础上,结合零矢量实现了双矢量固定开关频率控制。最后,基于RT-LAB半实物平台从稳态、暂态、中点电位波动方面进行验证,有效证明了所提控制策略的正确性和有效性。
文摘根据三相电压型脉宽调制(pulse width modulation,PWM)整流器的瞬时功率数学模型,在矢量空间中分别研究每个开关矢量对瞬时功率的不同影响,给出相应的作用图,并由此将整个空间重新划分为18个非固定扇区,提出一种新的具有通用性的开关矢量表,在此过程中探究直接功率(direct power control,DPC)控制的调制机制。这种新的开关矢量表不仅可以克服传统开关表对无功功率控制上的缺陷,获得更好的稳态和动态控制效果,而且可以对其他开关表的不足进行一定的解释。文中通过不同开关表的控制系统对比仿真与实验,验证了各项结论的正确性和实用性。
