由于零序滤波器自身的结构特点,无法滤除电网中除3的倍数次以外的谐波。根据变压器移相滤波原理,对变压器二次侧两个绕组采用星型和角型连接方式,使绕组之间的相电压产生30°的移相,经过绕组之间的谐波叠加消除5、7次等谐波。利用...由于零序滤波器自身的结构特点,无法滤除电网中除3的倍数次以外的谐波。根据变压器移相滤波原理,对变压器二次侧两个绕组采用星型和角型连接方式,使绕组之间的相电压产生30°的移相,经过绕组之间的谐波叠加消除5、7次等谐波。利用电磁暂态仿真软件(Power Systems Computer Aided Design,PSCAD)仿真,建立由移相变压器和零序滤波器组成的系统模型,对比分析仿真结果表明,移相变压器能够有效滤除网侧的5、7次等谐波,同时不影响零序滤波器的正常运行,移相变压器与零序滤波器的相互配合提高了滤波效果,为谐波治理的工程应用提供了一种新思路。展开更多
The application areas of conventional push pull converters are limited because of high voltage stress of switches (twice of input voltage). This paper presents a novel zero voltage and zero current switching (ZCS)...The application areas of conventional push pull converters are limited because of high voltage stress of switches (twice of input voltage). This paper presents a novel zero voltage and zero current switching (ZCS) PWM push pull three level converter in which the voltage stress of switches is input voltage. With phase shifted modulation strategy, the leading switches can only realize zero voltage switching (ZVS), and the lagging switches can realize ZCS when block capacitor and block diodes are added. Using the strategy, the converter overcomes the drawbacks presented by the conventional push pull converter, such as magnetic aberration, large switch loss, and voltage spike on switches, so it can get higher efficiency, and a wider application area. The operating principle of the new converter is analyzed and verified on a 600 W, 50 kHz experimental prototype. Several zero voltage and zero current switching PWM push pull three level converters are proposed.展开更多
文摘由于零序滤波器自身的结构特点,无法滤除电网中除3的倍数次以外的谐波。根据变压器移相滤波原理,对变压器二次侧两个绕组采用星型和角型连接方式,使绕组之间的相电压产生30°的移相,经过绕组之间的谐波叠加消除5、7次等谐波。利用电磁暂态仿真软件(Power Systems Computer Aided Design,PSCAD)仿真,建立由移相变压器和零序滤波器组成的系统模型,对比分析仿真结果表明,移相变压器能够有效滤除网侧的5、7次等谐波,同时不影响零序滤波器的正常运行,移相变压器与零序滤波器的相互配合提高了滤波效果,为谐波治理的工程应用提供了一种新思路。
文摘The application areas of conventional push pull converters are limited because of high voltage stress of switches (twice of input voltage). This paper presents a novel zero voltage and zero current switching (ZCS) PWM push pull three level converter in which the voltage stress of switches is input voltage. With phase shifted modulation strategy, the leading switches can only realize zero voltage switching (ZVS), and the lagging switches can realize ZCS when block capacitor and block diodes are added. Using the strategy, the converter overcomes the drawbacks presented by the conventional push pull converter, such as magnetic aberration, large switch loss, and voltage spike on switches, so it can get higher efficiency, and a wider application area. The operating principle of the new converter is analyzed and verified on a 600 W, 50 kHz experimental prototype. Several zero voltage and zero current switching PWM push pull three level converters are proposed.
