为更好地应用电力有源滤波器技术,通过最优化数学模型的建立介绍了瞬时无功功率理论的基本内容,所谓瞬时有功电流即保证三相瞬时总能量不变而三相传输损失最小的电流;空间基变换证明,电压和电流瞬时值从a b c三相变换到αβο三相为正...为更好地应用电力有源滤波器技术,通过最优化数学模型的建立介绍了瞬时无功功率理论的基本内容,所谓瞬时有功电流即保证三相瞬时总能量不变而三相传输损失最小的电流;空间基变换证明,电压和电流瞬时值从a b c三相变换到αβο三相为正交变换,说明三相三线制系统或无零序电压电流时三相到两相变换的合理性,从而将αβ变换与d q变换联系起来。最后指明系统电压畸变时不宜用基于该理论的谐波检测和无功补偿方法。展开更多
The structure and working principle of a two-cylinder four-stroke single-piston hydraulic free piston engine(HFPE) were introduced. The basic vibration equation of free piston assembly(FPA) was established based upon ...The structure and working principle of a two-cylinder four-stroke single-piston hydraulic free piston engine(HFPE) were introduced. The basic vibration equation of free piston assembly(FPA) was established based upon the energy conversion between the injected fuel and the friction together with the load. Both the theoretical and numerical results show that the vibration system of FPA is a nonlinear conservative autonomous system in one cycle. The FPA vibration is symmetric with constant amplitude when FPA is only driven by the compression pressure in the compression accumulator and that in the combustion chamber. When considering the friction and load, FPA could still achieve a stable vibration after a few cycles' adjustment whether the input energy is equal to the consumed energy or not. The vibration characteristics are different when FPA vibrates in the compression stroke and the expansion stroke, which is the unique feature of the single-piston HFPE.展开更多
文摘为更好地应用电力有源滤波器技术,通过最优化数学模型的建立介绍了瞬时无功功率理论的基本内容,所谓瞬时有功电流即保证三相瞬时总能量不变而三相传输损失最小的电流;空间基变换证明,电压和电流瞬时值从a b c三相变换到αβο三相为正交变换,说明三相三线制系统或无零序电压电流时三相到两相变换的合理性,从而将αβ变换与d q变换联系起来。最后指明系统电压畸变时不宜用基于该理论的谐波检测和无功补偿方法。
基金Project(51275451)supported by the National Natural Science Foundation of ChinaProject(51221004)supported by the Science Fund for Creative Research Groups of National Natural Science Foundation of China+1 种基金Project(2013CB035400)supported by the National Basic Research Program of ChinaProject(2011BAK03B09)supported by the National Key Technology R&D Program of China
文摘The structure and working principle of a two-cylinder four-stroke single-piston hydraulic free piston engine(HFPE) were introduced. The basic vibration equation of free piston assembly(FPA) was established based upon the energy conversion between the injected fuel and the friction together with the load. Both the theoretical and numerical results show that the vibration system of FPA is a nonlinear conservative autonomous system in one cycle. The FPA vibration is symmetric with constant amplitude when FPA is only driven by the compression pressure in the compression accumulator and that in the combustion chamber. When considering the friction and load, FPA could still achieve a stable vibration after a few cycles' adjustment whether the input energy is equal to the consumed energy or not. The vibration characteristics are different when FPA vibrates in the compression stroke and the expansion stroke, which is the unique feature of the single-piston HFPE.
