应用于塑料薄膜表面处理的电压源谐振变换器放电波形研究

电压源谐振变换器广泛应用于介质阻挡放电薄膜表面处理领域,其放电波形是影响薄膜表面处理效果的重要因素。首先分别对连续电流模式和断续电流模式下的电压源谐振变换器进行时域解析,证明了断续电流模式下放电电流波形能独立于功率而自由调节,而连续电流模式下放电电流波形与功率耦合而无法独立调节。然后以此为基础,设计并搭建了2台连续电流模式和断续电流模式的350 W/30 k Hz变换器样机,对双轴向聚丙烯、流延聚丙烯和聚酯三种材料样品进行了表面处理和效果对比。结果表明:在相同功率和频率下,与连续电流模式相比,断续电流模式中谐振电感越小,放电脉宽越窄,峰值电流越大,塑料薄膜的表面接触角越小,处理效果越好;断续电流模式下减小谐振电感可缩短放电脉宽,使得达到相同表面处理效果所需功率越小,实现了节能目的。

Analysis of Discharge Waveform in Voltage Source Resonant Converter Applied to Plastic Film Surface Treatment

Voltage source resonant converter is widely applied to film surface treatment with dielectric barrier discharge technique, and its discharge waveform is a significant factor which affects surface treatment effects. In this paper, a voltage source resonant converter working in continuous current mode(CCM) and discontinuous current mode(DCM) was analyzed in time domain respectively, and it was proved that the discharge waveform and power in DCM were decoupled and thus can be adjusted independently; however, they were coupled in CCM and cannot be adjusted independently. Then, two 350 W/30 kHz prototypes working in CCM and DCM were designed and built on this basis. Film treatment experiments were conducted on biaxially-oriented polypropylene(BOPP), casting polypropylene(CPP), and polyethylene terephthalate(PET), and the treatment effects were compared. Experimental results verified that under the same condition of power and frequency, a smaller resonant inductance in DCM contributed to thinner discharge pulse width and higher peak current, leading to a smaller contact angle and better treatment effect compared with CCM; for the same film treatment effect, a smaller resonant inductance in DCM can shorten the discharge pulse width, and thus contributed to smaller power and energy conservation.