The following equations are used to describe the critical parameters of resonant charging, including the resonant frequency (omega), the charging current, the voltage on the load capacitor, the maximum possible load capacitor voltage, and the efficiency of the energy transfer.
The poor efficiency when charging a capacitor through a resistor from a high-voltage power supply limits its application to low charging rates. In the resonance-charging concepts, the energy is transferred to the load capacitor in a single pulse, and it is not possible to compensate for capacitor leakage.
The charging mode ends when the capacitor voltage equals the output voltage of the power supply. The capacitor is continually refreshed by the power supply. During the discharge mode, the charging resistor isolates the power supply from the pulse load. The advantages of this technique are its simplicity, reliability, and low cost. FIGURE 21.3.
The rate at which the capacitor is charged and discharged is called the repetition rate, T, and may vary from 0.01 Hz for large capacitor banks to a few kHz for certain lasers. Recharging the capacitor voltage to a specified voltage is tasked to a capacitor charging power supply (CCPS).
Energy storage capacitors may be charged utilizing the same power electronic technology that has been applied in switching converters for constant power loads. Instead of charging the energy storage capacitor with a single pulse, switching converters can charge the capacitor with a series of pulses or pulse train.
Instead of charging the energy storage capacitor with a single pulse, switching converters can charge the capacitor with a series of pulses or pulse train. The peak current is reduced when charging with a series of pulses, thus improving the efficiency of the charging process.