Capacitor charging method and capacitor charger

A capacitor charging method in which a resonant type inverter section is operated by driving pulses at a fixed frequency to generate an ac voltage, the ac voltage is converted to a dc voltage, and a capacitor is charged using the dc voltage, comprising the steps of:

• a first step where a first type of driving pulse of the driving pulses has a fixed driving pulse width W1 determined in advance, which charges the capacitor by a boost voltage ΔVn (n is a natural number, ΔV1, ΔV2, . . . ) at each input of the first type of driving pulse;
• a second step which when a charging voltage V1 of the capacitor is a midpoint preset voltage value V3 that is lower than a target voltage value V2, charges by a boost voltage ΔVm (m is a natural number), by using a second type of driving pulse with a new, fixed driving pulse width W4 obtained with consideration of a change of input voltage to the resonant type inverter section;
• and
• a third step which charges by a third type of driving pulse having a controlled driving pulse width W5 (W5<W4) as required to boost the voltage by [V2−V1<ΔVm].

A capacitor charger in which a resonant type inverter section is switched by driving pulses at a fixed frequency to generate an ac voltage, the ac voltage is converted to a dc voltage by a rectifier, and a capacitor is charged using the dc voltage, comprising:

• a control section that controls such that the voltage of the capacitor is increased by a boost voltage ΔVn (n is a natural number, ΔV1, ΔV2, . . . ) at each input to the resonant type inverter section of a first type of driving pulse with a predetermined, fixed driving pulse width W1, calculates an nth first type of driving pulse with the fixed driving pulse width W1 when a relationship between a charging voltage V1 of the capacitor and a target voltage value V2 satisfies [V2−V1<ΔVn+ . . . ΔVn+k] (k is a natural number, k<n), or [V2−V1<ΔVn], calculates the number of driving pulses of a second type of driving pulse with a fixed driving pulse width W2 (W1>W2) that is supplied in order to increase the voltage of the capacitor by [V2−V1] when the relationship [V2−V1<ΔVn+ . . . ΔVn+k] or [V2−V1<ΔVn] is satisfied, drives the resonant type inverter section by the first type of driving pulse until a relationship [V2>V1>V2−V1<ΔVn+ . . . ΔVn+k] or [V2−V1<ΔVn] is satisfied for the charging voltage V1, drives the resonant type inverter section by the second type of driving pulse when the relationship [V2>V1>V2−V1<ΔVn+ . . . ΔVn+k] or [V2−V1<ΔVn] is satisfied, and charges the capacitor to the target voltage value V2.

A capacitor charger in which a resonant type inverter section is switched by driving pulses at a fixed frequency to generate an ac voltage, the ac voltage is converted to a dc voltage by a rectifier, and a capacitor is charged using the dc voltage, comprising:

• a control section that controls such that the voltage of the capacitor is increased by a boost voltage ΔVn (n is a natural number, ΔV1, ΔV2, . . . ) at each input to the resonant type inverter section of a first type of driving pulse with a predetermined, fixed driving pulse width W1, calculates an nth first type of driving pulse with the fixed driving pulse width W1 when a relationship between a charging voltage V1 of the capacitor and a midpoint preset voltage value V3, that is lower than a target voltage value V2, satisfies [V2−V1<ΔVn+ . . . ΔVn+k] (k is a natural number, and k<n), drives the resonant type inverter section by a second type of driving pulse of a fixed driving pulse width W3 obtained by another calculation when the relationship [V2−V1<ΔVn+ . . . ΔVn+k] is satisfied, calculates a controlled pulse width or the number of controlled driving pulses of a third type of driving pulse when a relationship [V2−V1<ΔVp] (p is a natural number) is satisfied for the charging voltage V1 of the capacitor, drives the resonant type inverter section by the third type of driving pulse, and charges the capacitor to the target voltage value V2.