Detailed Derivation and Minimization of the Equivalent Parasitic Capacitances of a High-Voltage Multiplier Based on the Complete Model

作者：Wang Jianing^*; de Haan Sjoerd W H; Abraham Jan

来源：IEEE Transactions on Industry Applications, 2015, 51(1): 362-372.

DOI：10.1109/TIA.2014.2330060

• High-voltage (HV) generator
• medical X-ray machine
• parasitic capacitance
• series-parallel resonant converter
• symmetrical Cockcroft-Walton multiplier

The authors' previous paper presents the complete model of parasitic capacitances in a high-voltage (HV) multiplier in the HV generator in a medical X-ray machine. The equivalent parasitic capacitance of the multiplier C-em based on the model is exhibited to interpret the role of the parasitic capacitances in circuit operation of the generator. Without derivation of the analytical expression of C-em, its dependence on the component parameters is directly shown, which leads to guidelines for minimization of C-em. However, the complete capacitance model has a complicated structure and contains voltage-dependent capacitances and voltage sources, which gives complexity to derivation of C-em as well as difficulties to clear understanding of the voltage dependence of C-em. Thus, this paper presents the detailed derivation and analytical expression of C-em. Exactly speaking, the key part of C-em, namely, the total chain capacitance C-Dcht that determines the voltage dependence of C-em, is conducted. A simple way is presented for the derivation of C-Dcht. The derivation enables a clear understanding of the voltage dependence of C-Dcht. Moreover, a design procedure for minimization of C-em is created, accompanied by a case study. It gives designers step-by-step rules to make an optimal HV multiplier with a minimum C-em.

• 出版日期2015-2