High Voltage Resonant Modular Capacitor Charger Systems With Energy Dosage

A concept and implementations of an innovative HV capacitor charger system based on resonant modular converter are described. This system may function also as a DC power supply. The charger will be a part of a HV pulsed power supply in a corona discharge system for pollution control applications. The system comprises N identical modules fed in parallel and connected in series at their outputs. They are clocked by a generator of shifted pulses (for operation in a multi-phase mode), and thus the ripple both at the input and the output is decreased dramatically. The switching frequency is continuously adjusted to minimize switching losses by ensuring virtually zero-current commutation. The inverters are based on a series-resonance topology in a half-bridge inverter with energy dosage characteristic. All modules have essentially the same resonant frequency, since the resonance is formed by the leakage inductance of the HV transformer and stable film capacitors. There are two means to regulate the output voltage. Wide-range regulation is provided by modules´ commutation on/off, while fine-tuning is done by the frequency regulation. Special attention was paid in designing the system to be capable of dealing with high EMI, an outcome of the electrical pulsed discharge.