TW201933746A - Power supply device and laser device capable of increasing the operating frequency of an intermittent load - Google Patents

Abstract

This invention provides a power supply device capable of increasing the operating frequency of an intermittent load. The power supply device (200) includes a capacitor set (202) and a charging power supply (210). An intermittent load (i.e., high frequency power supply (104)) is connected to the capacitor set (202). The charging power supply (210) includes a switching converter (212) and is configured to charge the capacitor set (202). The charging power supply (210) performs main charging to turn on the low side transistor (M1) of the switching converter (212) once by triggering the operation of the load (i.e., high frequency power supply (104)).

Description

Power supply device, laser device

The invention relates to a power supply device.

Laser processing devices are widely used as industrial processing tools. FIG. 1 is a block diagram of a laser processing apparatus 1r. The laser processing device 1r includes a laser light source 2 such as a CO ₂ laser, and a laser driving device 4r that supplies AC power to the laser light source 2 and excites it. The laser driving device 4r includes a DC power supply 6 and a high-frequency power supply 8. The DC power supply 6 is a constant voltage power supply, and stabilizes the DC voltage V _DC as a target value by using feedback control such as PID (Proportional-Integral-Differential) control or PI (Proportional-Integral) control. . The high-frequency power source 8 receives the DC voltage V _DC , converts it into an alternating voltage, and supplies it to the laser light source 2 as a load.
In the laser processing device 1r for drilling, the laser light source 2 is not continuously operated. That is, a relatively short light emission period of about several microseconds to about 10 microseconds and a stop period of the same degree or shorter than or longer than that are alternately repeated. In order to stabilize the output of the laser light source 2, the DC voltage V _DC must be within a predetermined allowable range (standard voltage range).

(Prior technical literature)
(Patent Literature)
Patent Document 1: Japanese Patent Application Laid-Open No. 2002-254186 Patent Document 2: Japanese Patent Application Laid-Open No. 8-168891

(Problems to be Solved by the Invention)
Fig. 2 is an operation waveform diagram of the laser processing apparatus 1r of Fig. 1. For ease of understanding, the vertical and horizontal axes of the waveform or timing diagrams referred to in this specification are appropriately enlarged and reduced, and for ease of understanding, the waveforms shown are also simplified or exaggerated or emphasized.
When the laser light source 2 is turned on and off, the high-frequency power source 8 repeats the operation period and the stop period. When the high-frequency power supply 8 is shifted from the stop period to the operation period, a response delay in feedback is generated in the DC power supply 6, and the DC voltage V _DC may drop, which may leave the allowable range. When the high-frequency power source 8 is shifted from the operation period to the stop period, the DC voltage V _DC may increase due to the feedback delay, and the frequency may deviate from the allowable range.
The present invention has been completed under such circumstances, and one of the exemplary objects of one aspect thereof is to provide a power supply device capable of increasing the operating frequency of a load that performs intermittent operations.

(Means to solve problems)
One aspect of the present invention relates to a power supply device. The power supply device includes a capacitor bank connected to a load for intermittent operation, and a charging power source including a switching converter and charging the capacitor bank. The charging power source performs main charging of the low-side transistor, which is switched on once when the load operation is triggered.
According to this aspect, the capacitor bank can be charged in parallel with the operation of the high-frequency power supply without waiting for the operation of the high-frequency power supply to be completed, so that the repetition frequency of the load can be increased.
The on-time of the low-side transistor can be updated for each operating cycle of the high-frequency power supply. This makes it possible to suppress the voltage drift of the capacitor bank.
The on-time of the low-side transistor can be the sum of the fixed on-time and the corrected on-time. The correction on-time in a certain operation cycle can be adjusted according to the error between the voltage of the capacitor bank and the target voltage in the previous operation cycle.
As a result of the main charging of the charging power source, when the voltage of the capacitor bank deviates from the standard voltage range, sub-charging and discharging can be performed. Rough charging is performed in the main charging, and precision charging with feedback control accompanying the on time is performed in the sub-charging and discharging, so that the voltage of the capacitor bank out of the standard voltage range can be restored to the standard voltage range.
The on-time of the low-side transistor in the main charge can be adjusted by PI (proportional / integral) control or PID (proportional / integral / derivative) control. In the next operation cycle where the operation cycle of the sub-charge occurs, the on-time of the sub-charge of the previous operation cycle can be used as the corrected on-time of the low-side transistor in the main charge. This makes it possible to optimize the amount of charge in main charging.
Another aspect of the present invention relates to a laser device. The laser device includes a laser light source, a high-frequency power source that intermittently supplies an alternating voltage to the laser light source, and the above-mentioned power source device using the high-frequency power source as a load.
In addition, any combination of the above constituent elements, or constituent elements of the present invention, or expressions of methods, devices, systems, etc., is also effective as aspects of the present invention.

(Effect of the invention)
According to one aspect of the present invention, the operating frequency of the load can be increased.

Hereinafter, the present invention will be described based on a preferred embodiment with reference to the drawings. The same or equivalent constituent elements, components, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are appropriately omitted. In addition, the embodiments are not limited to the invention, but are exemplified, and all the features or combinations described in the embodiments are not necessarily essential to the invention.
FIG. 3 is a block diagram of a laser device 100 including a power supply device 200 according to an embodiment. The laser device 100 includes a laser light source 102, a high-frequency power source 104, a high-level controller 106, and a power source device 200. The laser light source 102 is, for example, a CO ₂ laser. The high-level controller 106 generates an excitation signal S _EXC indicating the excitation (light emission) and stop of the laser light source 102.
An input of the high-frequency power source 104 is connected to the power source device 200, and an output thereof is connected to the laser light source 102. The DC voltage V _DC from the power source device 200 is supplied to the high-frequency power source 104. The high-frequency power source 104 intermittently supplies an AC drive voltage V _DRV to the laser light source 102 based on the excitation signal S _EXC . That is, the excitation signal S _EXC indicates the period of excitation (for example, high level), the high-frequency power source 104 becomes active, and the laser light source 102 is supplied with the AC driving voltage V _DRV . During the period when the excitation signal S _{EXC is} stopped (for example, low level), the high-frequency power source 104 becomes inactive, and the power supply to the laser light source 102 is stopped. A period during which the high-frequency power source 104 is switched is referred to as an operation period, and a period during which the switch is stopped is referred to as a stop period. The configuration of the high-frequency power supply 104 is not particularly limited as long as a known technique is used.
The power supply device 200 includes a capacitor group 202 and a charging power source 210. The capacitor bank 202 is connected to a high-frequency power source 104 as a load that performs intermittent operations. The capacitor pack 202 can be regarded as a direct current power source, such as a power storage element that supplies power to the high-frequency power source 104 with a single unit.
The charging power source 210 includes a switching converter 212 and a conversion controller 220. The charging power source 210 charges the capacitor group 202 so that the DC voltage V _DC generated in the capacitor group 202 is included in the standard voltage range V _TGT . The capacitance C of the capacitor group 202 is designed to be sufficiently large so that the DC voltage V _DC does not fall below the allowable range during the discharge based on the high-frequency power source 104.
The charging power source 210 performs main charging by triggering the operation of the high-frequency power source 104 as a load. For example, an excitation signal S _EXC or a signal based on the excitation signal S _EXC can also be input to the conversion controller 220, and when the excitation signal S _EXC transitions to a high level, that is, the action of the high-frequency power source 104 starts as a trigger, and the main Charging.
The switching converter 212 has a topology of a boost converter. Specifically, the switching converter 212 includes a reactor L ₁ , a low-side transistor M ₁ , and a high-side transistor M ₂ . The transistors M ₁ and M ₂ can be composed of a field effect transistor (FET: Field Effect Transistor), an insulated gate bipolar transistor (IGBT), or a bipolar transistor. Instead of the high-side transistor M _{2, a} diode can be used. The conversion controller 220 controls the low-side transistor M ₁ and the high-side transistor M ₂ .
During the main charging, the conversion controller 220 turns on the low-side transistor M _{1 of the} switching converter 212 once.
The above is the basic configuration of the laser device 100 according to the embodiment. Next, a basic operation of the laser device 100 will be described.
FIG. 4 is an operation waveform diagram of the laser device 100 according to the embodiment. The high-frequency power source 104 performs intermittent operation at a repetition frequency of several kHz and a duty ratio of about 5% according to the excitation signal S _EXC . FIG. 4 shows the operation in one cycle (one laser).
At time t ₀ , the excitation signal S _EXC becomes high level (activated), and becomes the excitation period T _EXC (t ₀ to t ₁ ). During the excitation period T _EXC , the high-frequency power source 104 performs a switching operation. During the excitation period T _EXC , the charge of the capacitor group 202 is discharged, and the DC voltage V _DC drops by an amount corresponding to the amount of drop ΔV. However, since the capacitance C of the capacitor group 202 is sufficiently large, the reduced DC voltage V _DC will not be lower than the lower limit of the standard voltage range V _TGT .
Conversion controller 220 to the excitation signal S _EXC to HIGH transition triggered by conduction to the low-side transistor M _1, the elapsed time after the on-time T _ON t _2, disconnect the low side transistor M _1.
While the low-side transistor M _{1 is} turned on, the current (reactor current) I _L flowing in the reactor L ₁ increases. At this time, the reactor current I _L on the low side transistor M ₁ flows, and therefore to the capacitor charging current I _CHG 202 is zero.
The switching controller 220 turns off the low-side transistor M ₁ at time t ₂ . If the low-side transistor M ₁ is turned off, the reactor current I _L decreases with time. The reactor current I _L at this time is used as the charging current I _CHG and is supplied to the capacitor group 202 via the internal diode (or external diode) of the high-side transistor M ₂ . As a result, the DC voltage V _{DC of the} capacitor bank 202 rises and returns to the original voltage level.
The on-time T _{ON will} be described. For simplicity, the amount of decrease ΔV depends on the output of the laser light source 102 and is considered to be substantially constant. During the excitation period of the laser light source 102, the amount of charge Q supplied from the capacitor group 202 to the high-frequency power source 104 becomes Q = C × ΔV. Therefore, the _ON time T _ON may be specified so that the time integral value of the charging current I _CHG coincides with the charge amount Q.
After the switching controller 220 turns off the low-side transistor M ₁ , the high-side transistor M ₂ can also be turned on as shown by a dotted line (synchronous rectification mode). In this case, the charging current I _CHG flows through the channel of the high-side transistor M ₂ . The above is the operation of the laser device 100.
The advantages of the power supply device 200 are clarified by comparison with the comparative technology. FIG. 5 is an operation waveform diagram of a power supply device of a comparative technology. In the comparison technique, the excitation signal S _EXC becomes a low level, and after the high-frequency power source 104 stops, the low-side transistor M _{1 is} turned on. Therefore, the period (repetition period) T _{CYC of} 1 cycle is represented by inequality (1).

On the other hand, according to the power supply device 200 of the embodiment, the capacitor bank 202 can be charged in parallel with the operation of the high-frequency power source 104 without waiting for the operation of the high-frequency power source 104 to end. Specifically, the period T _{CYC of} one cycle is represented by inequality (2).

As can be seen from the comparison of the inequality (1) and (2), according to the power supply device 200 of the embodiment, the cycle of one cycle of the high-frequency power source 104 as a load can be shortened, and the repetition frequency of the load can be increased.
The present invention is understood to be a block diagram or a circuit diagram of FIG. 3, or various devices and circuits derived from the above description, and is not limited to a specific configuration. In the following, not to narrow the scope of the present invention, but to help understand the nature of the invention or circuit operation, and to clarify these, a more specific configuration example or embodiment will be described.

(Variable on-time control)
If the output of the laser light source 102 can deviate from the design value, the amount of decrease ΔV of the voltage of the capacitor group 202 deviates from the design value. At this time, if the main charging is performed with a predetermined ON time T _ON , the recovery amount of the DC voltage V _DC generated by the charging and the decrease amount ΔV generated by the discharge are unbalanced, so that the DC voltage V _DC drifts.
Or, if the input voltage of the conversion controller 220 changes, the recovery amount of the DC voltage V _DC generated by the charging deviates from the design value, so an imbalance is generated between the DC voltage V _DC generated by the discharge and the DC voltage V _DC drifts. .
In order to suppress the drift of the DC voltage V _DC , the on-time T _{ON of the} low-side transistor M ₁ can be set to be variable and updated for each operation cycle of the load (high-frequency power source 104). FIG. 6 is a block diagram of the conversion controller 220A corresponding to the variable on-time control. The main part of the conversion controller 220A may be installed by a combination of a software program and a processor executing the software program, or may be installed by hardware. The control object 221 of the conversion controller 220A includes a pulse width modulator 230 or a driver (not shown), a switching converter 212, and a capacitor group 202.
In the conversion controller 220A, the on-time T _ON of the low-side transistor M _{1 is} the _sum of the fixed on-time T _{ON_FIX} and the corrected on-time ΔT _ON .

The fixed on-time T _{ON_FIX} can be specified according to the design value of the drop amount ΔV of the DC voltage V _DC for each _transmission . The correction on-time ΔT _ON can take zero, positive or negative.
The correction on-time ΔT _ON in a certain operation cycle is adjusted based on the error between the DC voltage V _DC and the target voltage V _REF at the end of the charging of the capacitor group 202 in the previous operation cycle. That is, the error between the DC voltage V _DC and the target voltage V _REF is detected, and the correction on-time ΔT _{ON of the} next operation cycle is adjusted so that the error voltages V _{ERR are} close to zero.
In a certain operation cycle i (i = 1, 2 ...), the charged voltage V _DC is converted into a digital value V _DC [i] by the A / D converter 222. The subtractor 224 subtracts the DC voltage value V _DC [i] from the target voltage value V _{REF to} generate an error value V _ERR [i]. The PID (proportional / integral / derivative) controller 226 generates a corrected on-time ΔT _ON [i + 1] of the next action cycle according to the error value V _ERR [i]. The adder 228 adds the fixed on-time T _{ON_FIX} and the corrected on-time ΔT _ON [i + 1] to determine the on-time T _ON [i + 1]. The pulse width modulator 230 generates a high-level pulse signal during the on time T _ON [i + 1], and drives the switching converter 212. Instead of the PID controller 226, a PI controller may be used.
The above is the description of the variable on-time control. FIG. 7 (a) is a diagram showing an example of the waveform of the DC voltage V _DC when the on-time is fixed, and FIG. 7 (b) is a diagram showing an example of the waveform of the DC voltage V _DC when the variable on-time control is performed .
As shown in FIG. 7 (a), if the on-time T _ON is fixed, an imbalance occurs between the charged charge amount and the discharged charge amount of the capacitor group 202 due to load fluctuations or input voltage fluctuations, so that the DC voltage V _{DC is} between The drift in each cycle eventually leads to a deviation from the standard voltage range V _TGT .
On the other hand, as shown in FIG. 7 (b), when the variable on-time control is introduced, the DC voltage V _DC is suppressed from drifting and can be maintained within the standard voltage range V _TGT . In addition, the ON time is corrected by PID control so that the DC voltage V _DC after charging in each cycle approaches the target voltage V _REF , so that it is possible to suppress the variation in the output energy of the laser light source 102.

(Sub charge and discharge)
After the primary charging, the DC voltage V _{DC of the} capacitor group 202 can also cause the standard voltage range V _{TGT to} deviate. This occurs under the following conditions. Even when the variable on-time control is introduced, the amount of drop ΔV in the DC voltage V _DC of the capacitor bank 202 changes rapidly, or the input voltage V _IN also changes rapidly. During the period when the DC voltage V _DC deviates from the standard voltage range V _TGT , the laser emission is prohibited by the high-level controller 106, and thus the productivity is lowered.
Therefore, as a result of the primary charging of the charging power source 210 once, when the voltage V _{DC of the} capacitor bank 202 _deviates from the standard voltage range V _TGT , sub-charging and discharging are performed. During the sub-charging and discharging, the amount of current supplied to or extracted from the capacitor group 202 is adjusted with a higher accuracy than the main charging. The sub charge and discharge can also be referred to as precision charge and discharge.
FIG. 8 is a block diagram of the conversion controller 220B corresponding to the sub charge and discharge. The conversion controller 220B includes a sub-charge / discharge controller 240 in addition to the conversion controller 220A of FIG. 6. During the main charging, the PID controller 226 is enabled.
After the main charging is completed, if the DC voltage V _DC deviates from the standard voltage range V _TGT , the sub-charge controller 240 is effective. The sub-charge / discharge controller 240 can adopt any one of P control, PI control, and PID control. The sub-charging and discharging controller 240 feedback controls the on-time T _{ON_FINE} so that the DC voltage V _DC approaches the reference voltage V _REF , that is, the error voltage V _ERR approaches zero, and controls the switching converter 212. In addition, a positive on-time T _{ON_FINE} can be associated with an additional charge, and a negative on-time T _{ON_FINE} can be associated with an additional discharge. When T _{ON_FINE} is negative, the switching converter 212 operates in a step-down mode in which the high-side transistor M _{2 is} turned on first.
Fig. 9 (a) and Fig. 9 (b) are timing diagrams illustrating the charge and discharge of the sub. At time t _{0, the} excitation signal S _EXC goes to a high level, main charging is performed, and the voltage V _{DC of the} capacitor bank 202 rises. As shown in FIG. 9 (a), as a result of the main charging, if the voltage V _{DC is} lower than the standard voltage range V _TGT , the sub charging is performed. Specifically, the conversion controller 220B feedback-controls the on-time T _{ON_FINE} so that the error voltage V _ERR approaches zero, and switches the low-side transistor M ₁ of the switching converter 212 at least once.
As shown in FIG. 9 (b), as a result of the main charging, if the voltage V _{DC is} higher than the standard voltage range V _TGT , the sub-discharge is performed. Specifically, the conversion controller 220B feedback-controls the on-time T _{ON_FINE} so that the error voltage V _ERR approaches zero, and switches the high-side transistor M ₂ of the switching converter 212 at least once.
By introducing the sub-charging and discharging and feedback control switching converter 212, the voltage V _DC outside the standard voltage range can be restored to the standard voltage range V _TGT .

(Switching from sub-charge to main charge)
In addition, in the next operation cycle where the operation cycle of the sub-charge _occurs , the on-time T _{ON_FINE of the} previous sub-charge can be used as the corrected on-time ΔT [i + 1 of the low-side transistor M ₁ in the main charge ]. This can be achieved by replacing the value of the integral term of the PID controller 226 with T _{ON_FINE} . FIG. 10 is a diagram illustrating the reflection of the on-time T _{ON_FINE of the} sub charge and discharge to the main charge.
FIG. 11 (a) is an operation waveform diagram when the control of FIG. 10 is not performed, and FIG. 11 (b) is an operation waveform diagram when the control of FIG. 10 is performed. When the control of FIG. 10 is not performed, as shown in FIG. 11 (a), a sub-discharge occurs in each cycle. That is, the repetition period becomes longer by an amount corresponding to the sub-discharge time. On the other hand, when the control of FIG. 10 is performed, as shown in FIG. 11 (b), the sub-discharges can be prevented from continuously occurring in a plurality of cycles, and therefore the repetition frequency of the laser can be increased.

(use)
Next, an application of the laser device 100 will be described. FIG. 12 is a diagram showing a laser processing apparatus 300 including a laser apparatus 100. The laser processing apparatus 300 irradiates a laser pulse 304 to the object 302 to process the object 302. The type of the object 302 is not particularly limited, and the types of processing include drilling, cutting, and the like, but are not limited thereto.
The laser processing device 300 includes a laser device 100, an optical system 310, a control device 320, and a stage 330. The object 302 is placed on the stage 330 and fixed as necessary. The stage 330 positions the object 302 based on the position control signal S ₂ from the control device 320, and scans the irradiation position of the object 302 and the laser pulse 304 relative to the object. The stage 330 may be 1-axis, 2-axis (XY), or 3-axis (XYZ).
The laser device 100 oscillates according to a trigger signal (excitation signal) S ₁ from the control device 320 to generate a laser pulse 306. The optical system 310 irradiates a laser pulse 306 to the object 302. The configuration of the optical system 310 is not particularly limited, and can include a lens group for guiding a light beam to the object 302, a lens or an aperture for beam shaping, and the like.
The control device 320 collectively controls the laser processing device 300. Specifically, the control device 320 intermittently outputs a trigger signal S ₁ to the laser device 100. The control device 320 generates a position control signal S ₂ for controlling the stage 330 based on the data (manufacturing method) describing the processing.
The present invention has been described based on several embodiments. Those skilled in the art will understand that these embodiments are examples, and various modifications can be made in the combination of these constituent elements or processing processes, and such modifications also fall within the scope of the present invention. This modification will be described below.
In the embodiment, the main charging and the sub charging and discharging are performed by a common converter. However, the present invention is not limited to this, and two systems of a main charging switching converter and a sub charging and discharging switching converter may be prepared.
The application of the power supply device 200 according to the embodiment is not limited to the power supply device 200, and it can be used for supplying a DC voltage to a load that performs intermittent operation.
According to the embodiment, the present invention has been described using specific words and expressions, but the embodiment only shows one side of the principle and application of the present invention. In the embodiment, the idea of the present invention provided in the scope of the patent application is not departed from. Within the range, many modifications or configuration changes are allowed.

100‧‧‧laser device

102‧‧‧laser light source

104‧‧‧High Frequency Power

106‧‧‧High controller

200‧‧‧ Power supply unit

202‧‧‧Capacitor bank

210‧‧‧ Charging Power

212‧‧‧Switch converter

220‧‧‧ Conversion Controller

226‧‧‧PID Controller

240‧‧‧ sub charge and discharge controller

L ₁ ‧‧‧Reactor

M ₁ ‧‧‧Low-side transistor

M ₂ ‧‧‧High-Side Transistor

300‧‧‧laser processing equipment

310‧‧‧ Optical System

320‧‧‧control device

330‧‧‧ carrier

FIG. 1 is a block diagram of a laser processing apparatus.

FIG. 2 is an operation waveform diagram of the laser processing apparatus of FIG. 1.

Fig. 3 is a block diagram of a laser device including a power supply device according to an embodiment.

FIG. 4 is an operation waveform diagram of the laser device according to the embodiment.

FIG. 5 is an operation waveform diagram of a power supply device of a comparative technology.

FIG. 6 is a block diagram of a conversion controller corresponding to a variable on-time control.

FIG. 7 (a) is a diagram showing an example of the waveform of the DC voltage V _DC when the on-time is fixed, and FIG. 7 (b) is a diagram showing an example of the waveform of the DC voltage V _DC when the variable on-time control is performed .

FIG. 8 is a block diagram of a conversion controller corresponding to a sub charge and discharge.

Fig. 9 (a) and Fig. 9 (b) are timing diagrams illustrating the charge and discharge of the sub.

FIG. 10 is a diagram illustrating the reflection of the on-time of the sub-charge to the main charge.

FIG. 11 (a) is an operation waveform diagram when the control of FIG. 10 is not performed, and FIG. 11 (b) is an operation waveform diagram when the control of FIG.

FIG. 12 is a diagram showing a laser processing apparatus including a laser device.

Claims (6)

A power supply device, comprising: a capacitor bank connected to a load for intermittent operation; and a charging power source including a switching converter and charging the capacitor bank, 组 the charging power source is triggered by the start of the operation of the load, The main charging of the low-side transistor of the aforementioned switching converter is conducted once. The power supply device according to item 1 of the scope of patent application, wherein the on-time of the aforementioned low-side transistor is updated for each operation cycle of the aforementioned load. The power supply device according to item 2 of the scope of patent application, wherein the on-time of the aforementioned low-side transistor is the sum of the fixed on-time and the corrected on-time, and the aforementioned corrected on-time in a certain operation cycle is based on its previous operation cycle. The voltage of the aforementioned capacitor bank and the target voltage are adjusted. The power supply device according to item 3 of the scope of the patent application, wherein: As a result of the aforementioned main power charging by the aforementioned charging power source, when the voltage of the aforementioned capacitor bank deviates from the standard voltage range, sub-charging and discharging are performed. The power supply device according to item 4 of the scope of patent application, wherein the corrected on-time of the low-side transistor in the main charge is adjusted by PI (proportional / integral) control or PID (proportional / integral / derivative) control. In the next operation cycle where the operation cycle of the sub-charge occurs, the on-time of the sub-charge in the previous operation cycle is used as the corrected on-time of the low-side transistor in the main charging. A laser device, comprising: (i) a laser light source; (ii) a high-frequency power source that intermittently supplies an alternating voltage to the aforementioned laser light source; and (ii) a power source device according to any one of claims 1 to 5.