An approach to a broad range of power control in voltage-source series-resonant inverters for corona discharge treatment-pulse-density-modulation

Abstract

Abstract-This paper implements a wide range of power control with pulse-density-modulation (PDM) in a voltagesource series-resonant inverter which realizes a corona discharge for surface treatment of film. The use of the pulse density-modulated inverter, or the P D M inverter, enables the employment of a three-phase diode bridge rectifier as a utility interface. The PDM inverter produces either a squar+wave ac voltage state or a zero voltage state at its ac terminals to control the discharge power of a corona surface treater. Moreover, it can achieve zero-current-switching ( Z C S ) and zero-voltageswitching (ZVS) in all the operating conditions, thus leading to a significant reduction of switching losses and electromagnetic noises. A 30 kHa, 6 k W surface treatment system consisting of a voltagesource PDM inverter, a s t e p u p transformer and a corona discharge treater shows the establishment of a stable corona discharge in an extremely wide range of power control from 0.5 70 t o 100 %, and therefore succeeds in performing both strong and weak surface treatment processes for film.

Dielectric Barrier Discharge Systems with HV Generators and Discharge Chambers for Surface Treatment and Decontamination of Organic Products

“…PDM modulation ensures even distribution of discharges over the entire length of the electrodes with a wide range of changes in average process power. The power regulation by means of PDM consists of sending in "packets" the maximum power with the frequency of a modulating generator with regulated filling [29,30,43]. The transistors in the inverter can work with ZVS soft commutation at a switching frequency greater than the resonant frequency.…”

“…The generator power circuit is relatively simple due to the unregulated DC voltage. The control system should also ensure that the transformer does not saturate, regardless of the length of the "packet" of power pulses and the pause time [43]. In particular, an even number of half-waves of the inverter output voltage should be maintained.…”

“…The basic control methods of high voltage alternating current (HVAC) generators that are used to generate DBD plasma are described in [29,30,43]. These are pulse amplitude modulation (PAM), pulse width modulation (PWM), phase shift-pulse width modulation (PS-PWM, PSC), pulse density modulation (PDM), and pulse frequency modulation (PFM).…”

Control and performance of a pulse-density-modulated series-resonant inverter for corona discharge processes

“…A broad range of power control is obtained by the PDM inverter which controls the duration of a zero-voltage state at its output terminals in synchronization with the resonant frequency of the series-resonant circuit. Although the PDM in this paper is somewhat similar in operating principle to the "discontinuous mode control" in [9], a significant difference in output voltage and current waveforms exists between the two [10]. A sophisticated control circuit based on a phase-locked loop (PLL) makes the PDM inverter achieve zero-voltage switching (ZVS) and quasi-zerocurrent switching (ZCS) in all the load conditions.…”

“…A sophisticated control circuit based on a phase-locked loop (PLL) makes the PDM inverter achieve zero-voltage switching (ZVS) and quasi-zerocurrent switching (ZCS) in all the load conditions. This paper pays much attention to the control circuit which follows that presented in [10]. The oscillating frequency of the PLL circuit always follows the resonant frequency; nevertheless, the actual average switching frequency of the IGBT's varies in a range of 600 Hz-30 kHz.…”