Full bridge Zero Voltage Switch PWM converter combines advantages of the PWM control technique and resonant technique. However, Full ZVS is achieved only under large load current because resonant tank of this circu...Full bridge Zero Voltage Switch PWM converter combines advantages of the PWM control technique and resonant technique. However, Full ZVS is achieved only under large load current because resonant tank of this circuit is made up of the parasitic capacitance of the power semiconductors and the leakage inductor of the transformer primary. In this paper two saturable inductors as magnetic switches are added to secondary, so output inductor is always reflected to primary and assists resonant transition. Full ZVS is achieved under lower load current. The above mentioned investigated results are validated by the computerized simulation and hardware circuit experiment.展开更多
The full bridge zero voltage zero current switching （ FB-ZVZCS ） , which could adjust the output power by keeping the duty ratio of lagging leg constant and changing the duty ratio of leading leg, was a common circu...The full bridge zero voltage zero current switching （ FB-ZVZCS ） , which could adjust the output power by keeping the duty ratio of lagging leg constant and changing the duty ratio of leading leg, was a common circuit of soft switching arc welding inverter power source. However, when the duty ratio of leading leg was reduced to zero, the output power stayed the constant value instead of becoming zero. The working status and waveforms of some major parameters were studied in this paper while the duty ratio of leading leg was zero. It was concluded that the minimum output power of soft switching inverter was related to the charging voltage of paraUel capacitors, and the output power also could be reduced by reducing the duty ratio of lagging leg. A novel two-stage continuous PWM control method that could switch working-mode between full bridge and half bridge was put forward in this paper. This kind of control method could further reduce the output power of soft switching inverter in order to meet the requirement of low heat input of sheet metal welding.展开更多
研究了一种用于三相电压型并网逆变器的新型直接功率控制策略——预测直接功率控制(Predictive Direct Power Control,P-DPC)。重点讨论了P-DPC不同的电压矢量选择原则和电压矢量作用时间的处理方法,以降低低次电流谐波成分,获得更好的...研究了一种用于三相电压型并网逆变器的新型直接功率控制策略——预测直接功率控制(Predictive Direct Power Control,P-DPC)。重点讨论了P-DPC不同的电压矢量选择原则和电压矢量作用时间的处理方法,以降低低次电流谐波成分,获得更好的动、静态性能。该P-DPC可实现恒定的开关频率,解决了传统开关表直接功率控制策略(LUT-DPC)开关频率不固定的弊病,继承了直接功率控制策略功率快速调节的固有特点,且无需旋转坐标变换和空间矢量脉宽调制。在一台2kVA并网逆变器实验样机上对传统LUT-DPC、矢量控制和P-DPC进行了仿真和实验研究。结果表明了本文提出方法的有效性和其在可再生能源开发利用中的工程实用前景。展开更多
文摘Full bridge Zero Voltage Switch PWM converter combines advantages of the PWM control technique and resonant technique. However, Full ZVS is achieved only under large load current because resonant tank of this circuit is made up of the parasitic capacitance of the power semiconductors and the leakage inductor of the transformer primary. In this paper two saturable inductors as magnetic switches are added to secondary, so output inductor is always reflected to primary and assists resonant transition. Full ZVS is achieved under lower load current. The above mentioned investigated results are validated by the computerized simulation and hardware circuit experiment.
文摘The full bridge zero voltage zero current switching （ FB-ZVZCS ） , which could adjust the output power by keeping the duty ratio of lagging leg constant and changing the duty ratio of leading leg, was a common circuit of soft switching arc welding inverter power source. However, when the duty ratio of leading leg was reduced to zero, the output power stayed the constant value instead of becoming zero. The working status and waveforms of some major parameters were studied in this paper while the duty ratio of leading leg was zero. It was concluded that the minimum output power of soft switching inverter was related to the charging voltage of paraUel capacitors, and the output power also could be reduced by reducing the duty ratio of lagging leg. A novel two-stage continuous PWM control method that could switch working-mode between full bridge and half bridge was put forward in this paper. This kind of control method could further reduce the output power of soft switching inverter in order to meet the requirement of low heat input of sheet metal welding.
文摘研究了一种用于三相电压型并网逆变器的新型直接功率控制策略——预测直接功率控制(Predictive Direct Power Control,P-DPC)。重点讨论了P-DPC不同的电压矢量选择原则和电压矢量作用时间的处理方法,以降低低次电流谐波成分,获得更好的动、静态性能。该P-DPC可实现恒定的开关频率,解决了传统开关表直接功率控制策略(LUT-DPC)开关频率不固定的弊病,继承了直接功率控制策略功率快速调节的固有特点,且无需旋转坐标变换和空间矢量脉宽调制。在一台2kVA并网逆变器实验样机上对传统LUT-DPC、矢量控制和P-DPC进行了仿真和实验研究。结果表明了本文提出方法的有效性和其在可再生能源开发利用中的工程实用前景。
