JP2007037204A - Charging apparatus for capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the drop of accuracy in charge due to the change of the capacitor capacity or the rector value of an LC resonance circuit, and also to charge the capacitor within a specified time even if there is high repetition. <P>SOLUTION: Switches 2 and 7 generate oscillating currents of half cycles in a LC resonance circuit composed of a capacitor 6 and a reactor 5 by ON control, and roughly charge a capacitor to voltage a little higher than the target voltage by OFF control when these oscillating currents reach specified values. A switch 10 discharges capacitor voltage by fine adjustment to the target voltage by the comparison between rough charge voltage and a charge voltage command in ON period. A controller 11 is provided with a capacity C computer 11D which computes the capacitance of the above capacitor, based on the internal temperature of the capacitor, and sets this capacitance as the parameter of the above set current calculation, as a correction control means which corrects one by one the charge error of rough charge voltage caused by the capacity change of the capacitor and the value change of the reactor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a capacitor charging device that charges a capacitor repeatedly at a high voltage up to a set voltage in a pulse power source that uses a power capacitor as a DC power source to generate high voltage and large current pulses, and in particular, LC resonance between a capacitor and a reactor. The present invention relates to a charging device that performs high-precision charging to a set voltage by performing coarse adjustment to charge a capacitor to a voltage slightly higher than a target voltage and then to discharge the capacitor to the target voltage.

A pulse power source used as a power source for an excimer laser, an ozonizer, or the like is configured as shown in FIG. 6, for example. The capacitor C ₀ is initially charged by the charging device HDC, and the voltage of the capacitor C ₀ is applied to the primary side of the pulse transformer PT through the saturable reactor SI ₀ by turning on the semiconductor switch SW, and the saturation operation of the saturable reactor SI ₀ The discharge current pulse-compressed by (magnetic switch operation) is supplied to the transformer PT as a primary current, and a boosted pulse current is generated on the secondary side of the transformer PT. The capacitor C ₁ is charged with this pulse current, the capacitor C ₂ in the next stage is charged with the discharge current pulse-compressed by the saturation operation of the saturable reactor SI ₁ , and further pulse-compressed with the saturation operation of the saturable reactor SI ₂ , By repeating these pulse compressions, the capacitor C _n (peaking capacitor) in the final stage is charged with a high voltage, and an ultrashort pulse is generated in a load LH such as a laser oscillator as a load by the saturation operation of the saturable reactor SI _{n in} the final stage.

In the above pulse generation, a pulse current is generated by repetitive charging and discharging of the capacitor C ₀ , this pulse current is magnetically compressed and supplied repeatedly to the load (for example, 4000 times per second). The charging device for the capacitor C ₀ for this purpose charges the capacitor to a voltage of a charging voltage command value (hereinafter referred to as a command value) within a predetermined time by the LC resonance operation of the reactor and the capacitor (see, for example, Patent Document 1). ).

  FIG. 7 shows an example of a main circuit configuration and a control device of a conventional charging device. When the semiconductor switches 2 and 7 are turned on, the DC power source 1 is applied to the reactor 5 to cause a short-circuit current to flow. When the semiconductor switches 2 and 7 are turned off, an oscillation current having a half cycle is applied to the LC resonance circuit that is a series connection circuit of the capacitor 6 and the reactor 5. Is generated. The control device 11 is composed of a control computer and implements a calculation function by software. When the oscillation current reaches the set current determined from the capacitance of the capacitor 6, the reactor value of the reactor 5, and the charging voltage command value, the switch 2 By controlling 7 to be off, the capacitor 6 is roughly charged to a voltage slightly higher than the target voltage. After that, the control device 11 turns on the switch 10 by comparing the coarse charging voltage of the capacitor 6 with the charging voltage command, and finely discharges the capacitor voltage to the target voltage through the resistor 9.

  In the above charging operation, in order to obtain high-speed and high-accuracy charging with respect to the command value, a quick charging period and a fine adjustment period are provided in one charging period. The battery is rapidly charged to a higher voltage and then discharged to the command value in a fine adjustment period. The reason for this is that it is difficult to accurately charge the command value using only the quick charge circuit, so the charge capacitor is charged to a voltage slightly higher than the command value using the quick charge circuit, and high-accuracy charging is achieved by discharging the fine adjustment circuit. To do.

  The operation during the quick charge period will be described (see FIG. 8 for a waveform diagram). In FIG. 7, when the switch 2 and the switch 7 are simultaneously turned on by the control device 11, a current flows through the circuit along a path indicated by a broken line arrow A and accumulates as electromagnetic energy in the reactor 5. Next, when the switch 2 and the switch 7 are turned off at the same time, a current flows through the circuit along the path indicated by the broken line arrow B, and all the energy stored in the reactor 5 is transferred to the capacitor 6 and the capacitor 6 is charged. The reactor value of the reactor 5 is L, the capacitance of the capacitor 6 is C, the current of the broken line arrow A when the switch 2 and the switch 7 are turned off is I, and the voltage of the capacitor 6 when the current of the broken line arrow B finishes flowing is V (below) , Called the coarse charge voltage), from the law of conservation of energy,

Holds. The charging device uses the above equation to charge the capacitor 6 to a target voltage (voltage several percent higher than the command value) V. That is, the current i is always detected and the following calculation is performed in real time, and the switch 2 and the switch 7 are turned off when this equation is established.

  The operation during the fine adjustment period will be described. When the control device 11 turns on the switch 10 immediately after finishing the rough charging of the capacitor 6, a current flows through the circuit along the path indicated by the broken line arrow C, and the energy charged in the capacitor 6 is consumed by the resistor 9. In the fine adjustment period, the command value and the voltage of the capacitor 6 are always compared (by a comparator or the like), and the switch 10 is turned on until the voltage of the capacitor 6 matches the set value V *.

  The control device 11 basically includes an on / off control unit 11A that performs on / off control of the switches 2, 7, and 10, and a determination unit 11B that obtains an off timing of the switch 10 based on detection of the capacitor voltage Vc. And an arithmetic unit 11C that obtains the off timing of the switches 2 and 7 based on the detection of the current i according to Equation 2.

  FIG. 9 shows an example of a main circuit configuration and a control device of another conventional charging device. 7 differs from FIG. 7 in that a DC current boosted by an inverter 2A, a step-up transformer 3 and a rectifier circuit 4A is supplied to the reactor 5 instead of the switch 2, and a circulating current path is supplied by the rectifier circuit 4A instead of the diode 4. Form. As in the case of FIG. 7, the charge control provides a quick charge period and a fine adjustment period in one charge period, and rapidly charges the load capacitor to a voltage several percent higher than the command value during the quick charge period. During the fine adjustment period, the battery discharges to the command value.

10 and 11 show an example of a main circuit configuration and a control device of another conventional charging device, and a waveform diagram thereof is shown in FIG. FIG. 10 omits the switch 7 from the configuration of FIG. 7, the switch 2 is turned on to charge the reactor 5 and the capacitor 6 through the path A, and the switch 2 is turned off and the diode B is passed through the diode 4 to pass the reactor energy. The battery is charged and the voltage is finely adjusted in the path C when the switch 10 is turned on. Similarly, in FIG. 11, the switch 7 is omitted from the configuration of FIG. 9, and the capacitor 6 is charged and discharged along the paths A, B, and C.
JP 2005-117766 A

  In the conventional device, the capacitance of the capacitor 6 changes due to the change of the internal temperature due to the change of the ambient temperature and the operation rate of the device. Moreover, the reactor value of the reactor 5 may also change with the change of ambient temperature and the operation rate of an apparatus.

  By transforming Equation 1 above,

Therefore, when the capacitance changes from C to C ′, the coarse charge voltage changes as follows.

  Further, when the reactor value changes from L to LI, the coarse charge voltage changes as follows.

  As described above, when the capacitance of the capacitor 6 decreases due to a temperature change or the like, the coarse charge voltage increases from Equation 4-1, and when the reactor value of the reactor 5 similarly increases from Equation 4-2, the coarse charge voltage increases. There is a problem.

  (1) The discharge power of the resistor 9 increases, leading to an increase in the size of the resistor 9 and a decrease in device efficiency.

  (2) In some cases, the coarse charge voltage increases excessively, and it is impossible to discharge to the set value V * within the fine adjustment period (see FIG. 13).

  (3) If the resistance value of the resistor 9 is reduced for the purpose of preventing the above case, the discharge voltage dV / dt increases and the charging accuracy deteriorates.

  The objective of this invention is providing the charging device of the capacitor | condenser which solved said subject.

  The present invention that solves the above-described problems includes a correction control means that sequentially corrects a charging error of a coarse charging voltage caused by a change in capacitance of a capacitor or a change in reactor reactor value, and has the following configuration.

(1) A DC power source is applied to an LC resonance circuit in which a capacitor and a reactor are connected in series to generate a half-cycle oscillating current, and the oscillation is changed to a set current determined from the capacitance of the capacitor, the reactor reactor value, and a charging voltage command value. A charging circuit that roughly charges the capacitor to a voltage slightly higher than the target voltage when the current reaches, and a discharging circuit that finely adjusts the capacitor voltage to the target voltage by comparing the rough charging voltage of the capacitor and the charging voltage command A capacitor charging device comprising:
A correction control means is provided for sequentially correcting a charging error of the rough charging voltage caused by a change in capacitance of the capacitor or a change in reactor reactor value.

  (2) The correction control unit is a capacitance C calculation unit that calculates the capacitance of the capacitor based on the internal temperature of the capacitor and sets the capacitance as a variable of the set current calculation. And

  (3) The correction control means calculates the capacitance of the capacitor from the measurement result of the coarse charge voltage, the fine adjustment time, and the charge voltage after the fine adjustment, and uses the capacitance as a variable for the set current calculation. It is characterized in that it is a capacity C calculating means for setting.

  (4) The correction control means estimates the coarse charge voltage from the fine adjustment time, and corrects a coarse charge set value gain for adjusting the coarse charge voltage set value using the estimated value. It is characterized by an estimation means.

  (5) The correction control means calculates a reactor value of the reactor based on the application time of the DC power supply and the oscillating current at that time, and calculates the reactor L as a variable of the set current calculation It is characterized as a means.

  (6) When the previous discharge operation time exceeds a certain time, the correction control means turns on the coarse charge set value gain for adjusting the coarse charge voltage set value for the next and subsequent steps in steps. It is characterized by the time determination means.

  (7) The charging time is calculated from the voltage of the DC power supply.

  As described above, according to the present invention, since the correction control means for sequentially correcting the charging error of the coarse charging voltage caused by the change in the capacitance of the capacitor or the change in the reactor value of the reactor is provided, the charging accuracy due to the fluctuation of the capacitor capacity or the reactor value is provided. The battery can be charged within a predetermined time even at higher repetitions. In addition, the charging control for achieving such an effect requires the addition of a calculation function of the control device, and the device is hardly increased in size and cost.

(Embodiment 1)
FIG. 1 shows an embodiment of the present invention, and the main circuit configuration is the same as FIG. As in FIG. 7, the control device 11 includes an on / off control unit 11A that performs on / off control of the switches 2, 7, and 10, a determination unit 11B that obtains the off timing of the switch 10 based on detection of the capacitor voltage Vc, And an arithmetic unit 11C that obtains the off timing of the switches 2 and 7 based on the detection of the current i according to Equation 2. Furthermore, a charging voltage correction means is also provided in consideration of fluctuations in the voltage Vdc of the DC power supply 1.

  Here, in the present embodiment, a capacitance C calculation unit 11D that calculates the capacitance C based on the temperature of the capacitor 6 and corrects it as the capacitor capacitance C in the calculation unit 11C is provided. The temperature of the capacitor 6 is detected by the temperature detector 12. The temperature detector 12 is realized, for example, with a configuration in which a temperature sensor is inserted into the tank of the capacitor 6.

  The capacitance of the capacitor 6 can be estimated by measuring its internal temperature, and the capacitance C calculation unit 11D captures the temperature detection value from the temperature detector 12 immediately before the charging of the capacitor 6 starts, and the capacitor is calculated from the detected temperature. 6 is calculated, and the calculated capacitance C of the capacitor 6 is substituted as a variable into the calculation formula (Formula 2) of the calculation unit 11C.

  Conventionally, since the control is performed with the capacitance C of the capacitor 6 fixed, an error also occurs in the rough charge voltage V due to an error from the actual capacitance. In the present embodiment, an actual electrostatic capacity is calculated and substituted into Equation 2 to accurately control the rough charge voltage, which in turn is a conventional problem. Decreased efficiency, (2) Discharging to the set value V * within the fine adjustment period, (3) Decreasing the resistance value of the resistor 9 increases the discharge voltage dV / dt and deteriorates the charging accuracy. Can be resolved.

(Embodiment 2)
FIG. 2 shows the configuration of the present embodiment. Instead of the capacitance C calculation unit 11D in FIG. 1, the capacitance of the capacitor 6 is determined based on the measurement result of the coarse charge voltage, the ON time of the switch 10 and the charge voltage after fine adjustment. As in the first embodiment, a capacitance C calculation unit 11E that substitutes the calculated capacitance C of the capacitor 6 into Equation 2 is provided.

  The capacitance C of the capacitor 6 at the time of the previous charging is obtained by the following equation 6 where T is the on time of the switch 10, V1 is the coarse charging voltage, V2 is the fine adjustment voltage, and R is the value of the resistor 9. The capacity C calculation unit 11E performs the above calculation.

  According to the present embodiment, the same effect as that of the first embodiment is applied to the second and subsequent operations when the charging operation is performed at a short interval (an interval at which the change in capacitance due to the internal temperature change of the capacitor 6 is negligible). effective. However, the coarse charge voltage cannot be obtained at the first time when the charging operation is started, but an accurate coarse charge voltage can be obtained after the second shot. Also, the detector for current i can be eliminated.

(Embodiment 3)
FIG. 3 shows the configuration of the control device of this embodiment. The rough charging voltage estimation unit 11F estimates the rough charging voltage value from the ON time T of the switch 10 without measuring the charging voltage, and reflects an error from the target value in the next set value.

  The estimated value V1 ′ of the rough charge voltage at the previous charge can be obtained from the above equation 6 by the following calculation, where T is the ON time of the switch 10 and V * is the charge voltage command 16 (command value). .

  Moreover, since the command value of the rough charging voltage input to the control device 11 is a value obtained by multiplying the charging voltage command by the gain adjusting unit 11G, the value of V1 ′ obtained from the value of the gain G by Expression 7 is obtained. Next, the next rough charge voltage can be controlled by changing the following equation.

  However, G0: a fixed value of the gain before gain adjustment, the rate of overcharging the load capacitor (a value several percent larger than 1), g: a variable with an initial value of, for example, 1, and the charge voltage command of the previous charge If the value is V * and the value of the variable g is g1, the value g2 of the variable g used at the next charging can be obtained by the following equation.

  Therefore, the gain value G used at the next charging is expressed by the following equation:

This is used as the gain value at the next charging.

In addition, when the actual rough charge voltage value is V1 ′ with respect to the previous input value V * × G0 × g1 of the calculation unit 11C, for example, the value of the next charge voltage command is also V *, the input value is V *. Since × G0 ² × g1 × exp (−T / CR), the rough charge voltage value is expressed by the following formula:

Thus, the rough charge voltage can be controlled to a target value (however, an error occurs because the capacitance C of the capacitor 6 is a fixed constant).

  According to the present embodiment, the capacitance of the capacitor 6 used in (Equation 8) is not accurate because it is a fixed constant. However, the estimated value V1 of the rough charging voltage is compared with the amount of change in the capacitance. Since the error of 'is small, the same effect as in the second embodiment can be obtained. Further, it is not necessary to detect the rough charge voltage value.

(Embodiment 4)
FIG. 4 shows the configuration of the control device of this embodiment, and a reactor L calculation unit 11H is provided. The reactor L calculation unit 11H calculates the value of the reactor 5 from the ON time of the switch 2 and the switch 7 and the current value at that time, and uses the calculated reactor value L of the reactor 5 as a variable as the reactor value of the calculation unit 11C. substitute.

  When the on time of the switch 2 and the switch 7 is T2, the current value of the reactor 5 at that time is I2, and the DC voltage is E, the value L of the reactor 5 can be obtained from the following equation.

  According to this embodiment, when the value of the reactor 5 changes with temperature etc., the same effect as Embodiment 1 is acquired by substituting the calculated reactor value L to (Formula 2).

(Embodiment 5)
FIG. 5 shows the configuration of the control device of this embodiment, and an on-time determination unit 11I is provided. When the on-time of the switch 10 at the previous charging exceeds a certain time, the on-time determining unit 11I changes the coarse charge setting value gain G of the gain adjusting unit 11G used after the next time stepwise.

  The on-time T of the switch 10 is as shown in (Expression 6). However, when T becomes longer than the fine adjustment period, as described above, the coarse charge voltage increases excessively and reaches the set value V * within the fine adjustment period. It becomes impossible to discharge completely.

  Therefore, in the present embodiment, an appropriate time T2 shorter than the fine adjustment period is set in the on-time determination unit 11I, and when the on-time T of the switch 10 exceeds T2, the gain adjustment unit 11G used from the next time onward is set. The gain value G is adjusted based on the following equation using (Equation 8-3). However, the value of the gain adjustment unit 11G up to the previous time is set to G0 × g1.

  According to the present embodiment, the gain G obtained by (Equation 10) is a constant that can be calculated in advance, and in order to solve (Equation 6), (Equation 8), and (Equation 9) in Embodiments 2 to 4, respectively. Necessary arithmetic circuits are not required.

(Embodiment 6)
The control method of the quick charge period is to perform the calculation of (Equation 2) in real time while detecting the current i of the wavy arrow A. If the DC voltage _VDC is detected immediately before the start of charging, the switch 2 and the switch 7 on-time T can be calculated. For example, in the embodiment shown in FIGS. 1 to 5, when the value of the DC voltage V _DC is E, the ON time T can be obtained from the following equation.

  In this embodiment, the feedforward control method as described above is applied to the first to fifth embodiments.

(Modification)
Although each of the first to sixth embodiments described above is applied to the main circuit configuration of FIG. 7, it can be applied to the ones of FIGS. 9 to 11 to obtain equivalent operational effects.

The main circuit structure and control apparatus which show Embodiment 1 of this invention. The main circuit structure and control apparatus which show Embodiment 2 of this invention. The main circuit structure and control apparatus which show Embodiment 3 of this invention. The main circuit structure and control apparatus which show Embodiment 4 of this invention. The main circuit structure and control apparatus which show Embodiment 5 of this invention. Configuration example of a pulse power supply. Main circuit configuration and control device (part 1) of a conventional charging device. FIG. 7 shows current and voltage waveforms. The main circuit structure and control apparatus (the 2) of the conventional charging device. Main circuit configuration and control device (part 3) of a conventional charging device. The main circuit structure and control apparatus of the conventional charging device (the 4). The current / voltage waveform of FIG. Capacitor voltage waveform when the coarse charge voltage becomes high and it becomes impossible to discharge to the set value within the fine adjustment period.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 DC power supply 2, 7, 10 Switch 2A Inverter 3 Step-up transformer 4, 8 Diode 4A Rectifier circuit 5 Reactor 6 Capacitor 9 Resistance 11 Controller 11A ON / OFF control part 11B Determination part 11C Operation part 11D Capacity C calculation part 11E Capacity C Calculation unit 11F Coarse charge voltage estimation unit 11G Gain adjustment unit 11H Reactor L calculation unit 11I On time determination unit

Claims (7)

A DC power supply is applied to an LC resonance circuit in which a capacitor and a reactor are connected in series to generate a half-cycle oscillating current, and the oscillating current reaches a set current determined from the capacitance of the capacitor, the reactor reactor value, and the charging voltage command value. A charging circuit for roughly charging the capacitor to a voltage slightly higher than the target voltage, and a discharging circuit for finely adjusting and discharging the capacitor voltage to the target voltage by comparing the rough charging voltage of the capacitor and the charging voltage command. A capacitor charging device,
A capacitor charging apparatus comprising correction control means for sequentially correcting a charging error of a coarse charging voltage caused by a change in capacitance of the capacitor or a change in reactor reactor value.   The correction control unit is a capacitance C calculation unit that calculates the capacitance of the capacitor based on an internal temperature of the capacitor and sets the capacitance as a variable of the set current calculation. Item 2. The capacitor charging device according to Item 1.   The correction control means calculates a capacitance of the capacitor from the measurement result of the rough charge voltage, fine adjustment time, and charge voltage after fine adjustment, and sets the capacitance as a variable for the set current calculation. The capacitor charging apparatus according to claim 1, wherein the capacitor calculating unit is a C calculating unit.   The correction control means estimates the coarse charge voltage from the fine adjustment time, and coarse charge voltage estimation means for correcting a coarse charge set value gain for adjusting the coarse charge voltage set value by the estimated value; The capacitor charging device according to claim 1, wherein   The correction control means calculates a reactor value of the reactor based on an application time of the DC power supply and the oscillating current at that time, and is a reactor L calculation means for setting the reactor value as a variable for the set current calculation. The capacitor charging device according to claim 1.   The correction control means is an on-time determination means for changing the coarse charge setting value gain for adjusting the coarse charge voltage setting value for the next and subsequent times stepwise when the previous discharge operation time exceeds a certain time. The capacitor charging device according to claim 1, wherein The said charging time is calculated from the voltage of the said DC power supply, The charging device of the capacitor | condenser of any one of Claims 1-6 characterized by the above-mentioned.

Images