Capacitor charging method and charging apparatus

A capacitor charging apparatus for charging a load capacitor to a set voltage, comprising:

• a voltage converter which switches a dc power supply voltage;
• an inductance circuit which provides a resonant current for charging the load capacitor by applying the switched dc voltage and resonating with the load capacitor;
• and
• a switch circuit which short-circuits the output side of the inductance circuit when the charge voltage of the load capacitor has reached the set voltage so as to prevent an inertial current, produced by electromagnetic energy accumulated in the inductance circuit, from flowing to the load capacitor, the switch circuit being provided on the output side of the voltage converter.

A capacitor charging method for charging a load capacitor to a set voltage, comprising the steps of:

• charging the load capacitor by using a voltage converter to switch a dc power supply voltage, and supplying a resonant current to an inductance circuit by using resonance with the load capacitor and application of the dc voltage;
• switching OFF the voltage converter when the charge voltage of the load capacitor has reached a target value, which is lower than the set voltage;
• further charging the load capacitor with an inertial current, produced by electromagnetic energy accumulated in the inductance circuit;
• and
• when the charge voltage of the load capacitor has reached the set voltage, switching ON a switch circuit, provided on the output side of the voltage converter, bypassing the inertial current from the load capacitor and so as to prevent the inertial current from flowing the load capacitor.

A capacitor charging method for charging a load capacitor to a set voltage, comprising the steps of:

• charging the load capacitor by using a voltage converter to convert an applied dc power supply voltage to a predetermined dc voltage, and supplying a resonant current to an inductance circuit by using resonance with the load capacitor and application of the dc voltage;
• calculating a boost in charge voltage of the load capacitor by prediction within in an operating delay td from generating a charge stop command and the actual stop of charging, and stopping charging of the load capacitor by generating the charge stop command in anticipation of the boost in charge voltage;
• and
• short-circuiting the output side of the inductance circuit by switching ON a switch circuit, provided on the output side of the voltage converter, preventing an inertial current, produced by electromagnetic energy which has accumulated in the inductance circuit, to the load capacitor.

A capacitor charging apparatus which charges a load capacitor to a set voltage, comprising:

• a voltage converter which switches a dc power supply voltage;
• an inductance circuit which supplies a resonant current for charging the load capacitor by using resonance with the load capacitor and application of the dc voltage;
• a switch circuit which is provided on the output side of the voltage converter and, when switched ON, short-circuits the output side of the inductance circuit so as to prevent an inertial current, produced by electromagnetic energy which has accumulated in the inductance circuit, to the load capacitor;
• an ON signal generator which generates an ON signal for switching ON the switch circuit in compliance with a charge stop command;
• and
• an arithmetic circuit which calculates the charge voltage boost of the load capacitor during the operating delay between the generating of the ON signal by the ON signal generator and the stopping of charging as a result of the switch circuit switching ON, and transmits the charge stop command to the ON signal generator in anticipation of the charge voltage boost.

A capacitor charging apparatus which charges a load capacitor to a set voltage, comprising:

• a voltage converter which switches a dc power supply voltage;
• an inductance circuit which supplies a resonant current for charging the load capacitor by using resonance with the load capacitor and application of the dc voltage;
• a switch circuit which is provided on the output side of the voltage converter and, when switched ON, short-circuits the output side of the inductance circuit so as to prevent an inertial current, produced by electromagnetic energy which has accumulated in the inductance circuit, to the load capacitor;
• an ON signal generator which generates an ON signal for switching ON the switch circuit in compliance with a charge stop command;
• and
• a charge voltage detector which detects the charge voltage of the load capacitor as a charge voltage detect signal Vd;
• and
• an arithmetic circuit which calculates (Vd+td×dVd/dt) based on the charge voltage detect signal Vd and an operating delay td relating to the switch circuit, and, when (Vd+td×dVd/dt)=a predetermined reference voltage Vr, transmits the charge stop command to the ON signal generator.

A method for charging a load capacitor in stages comprising:

• a first step of charging the load capacitor to a predetermined voltage by supplying a resonant current, generated by resonance of an inductance circuit and a resonant capacity, from a power;
• a second step of cutting-off the resonant current to the load capacitor, and simultaneously maintaining the energy accumulated in the inductance circuit while circulating the energy;
• a third step of again charging the load capacitor to a set voltage, which is set in each charge cycle and is determined in consideration of load conditions, by supplying the resonant current to the load capacitor via the inductance circuit from the power;
• and
• a fourth step of again cutting-off the resonant current to the load capacitor, and simultaneously discharging the energy accumulated in the inductance circuit.

A capacitor charging apparatus which charges a load capacitor to a set voltage in stages, comprising:

• an inductance circuit which supplies a resonant current for charging the load capacitor by using resonance with the load capacitor and application of a predetermined dc voltage;
• a voltage converter which switches a dc power supply voltage, and is provided with a feedback circuit which, during a predetermined period, circulates energy, which has accumulated in the inductance circuit, while feeding back the energy to a dc power which generates the dc power supply voltage;
• a switch circuit which shuts off an inertial current, produced by the energy which has accumulated in the inductance circuit, from the load capacitor;
• a comparator which compares a reference voltage, set to a predetermined constant reference voltage or a variable reference voltage which is calculated from load conditions after each charge cycle, with the charge voltage of the load capacitor;
• a controller which firstly charges the load capacitor to an intermediate voltage corresponding to the constant reference voltage based on the comparison result from the comparator, and then stops the charging of the load capacitor, circulates the current of the inductance circuit by using the feedback circuit, and subsequently sets the variable reference voltage as the reference voltage, switches OFF the switch circuit and restarts the charging of the load capacitor, charges the load capacitor to the set voltage based on the comparison result of the comparator, and then, switches ON the switch circuit and bypasses the inertial current from the load capacitor.

A capacitor charging method for charging a load capacitor to a target voltage, comprising the steps of:

• using a main charger to convert an applied dc power supply voltage to a predetermined dc voltage, and charging the load capacitor by supplying a resonant current, generated by resonance with the load capacitor and application of the dc voltage, to the inductance circuit;
• stopping the charging of the load capacitor by using the main charger to generate a charge stop command when the charge voltage of the load capacitor has reached a predetermined voltage near the target voltage, and preventing an inertial current, produced by energy which has accumulated in the inductance circuit, from flowing to the load capacitor by short-circuiting the output side of the inductance circuit by using a bypass switch circuit;
• and circuit
• thereafter, using an auxiliary charger, which is connected in parallel to the main charger, to charge to 100% of the target voltage and auxiliarily charge the discharge of the load capacitor.

A capacitor charging apparatus which charges a load capacitor to a target voltage, comprising:

• a main charger comprising a voltage converter which converts a dc power supply voltage to a predetermined dc voltage, an inductance circuit which supplies a resonant current for charging the load capacitor by using resonance with the load capacitor and application of the predetermined dc voltage, and a bypass switch circuit which short-circuits the output side of the inductance circuit by using a charge stop command, and prevents an inertial current, produced by electromagnetic energy of the inductance circuit, from flowing to the load capacitor, the bypass switch circuit being provided on the output side of the voltage converter;
• and
• an auxiliary charger which is connected in parallel with the main charger;
• the main charger charging the load capacitor, and generating a charge stop command when the charge voltage of the load capacitor has reached a predetermined voltage near the target voltage, shutting off the load capacitor from the electromagnetic energy of the inductance circuit by using the bypass switch circuit;
• and
• the auxiliary charger charging to 100% of the target voltage and auxiliarily charging the discharge of the load capacitor.