JP4526879B2 - DC power supply - Google Patents

Description

  The present invention relates to a DC power supply device used for a load such as a plasma generator.

  In general, a power source for plasma generation used in a sputtering apparatus is required to have characteristics such that an excessive current does not flow when an arc is generated. Moreover, when an arc occurs, it is necessary to extinguish the arc at high speed.

  When a voltage type power supply is used for such a power supply, a large capacitor is often connected to the output, and when an arc occurs in the output, a discharge current flows from the capacitor.

  Further, when the output voltage decreases due to the occurrence of an arc, the operation is performed so as to maintain the voltage at a constant value and further output. For this reason, when an arc occurs, an overcurrent may flow or the arc may continue for a long time, which may adversely affect the load.

  In order to solve the above problems, a DC power supply device using an inverter circuit that operates as a power supply and easily controls current when output is excessive is known (see Patent Document 1).

Such a DC power supply device normally includes an input smoothing circuit (input smoothing unit), an inverter circuit (inverter unit), a transformer, and an output rectifying and smoothing circuit (output rectifying and smoothing unit). This inverter circuit forms a full bridge circuit composed of four first to fourth switching elements, and turns on / off alternately the first, fourth switching element, and the second and third switching elements. Converts voltage to AC voltage. The AC voltage is boosted by a transformer, and the boosted AC voltage is rectified by a rectifier circuit and output as a DC voltage.
JP 2004-40962 A

  By the way, in the DC power supply described above, the output is controlled to a predetermined value by making the width of the switching element drive pulse of the inverter unit variable. On the other hand, in this DC power supply device, since the output voltage range needs several V to several hundred V (1000 V or more at the time of plasma activation), the control range is wide and the width of the drive pulse needs to be varied widely. The output ripple varies greatly depending on the load state.

  Further, since this DC power supply device is of a current type, a special operation is required for appropriately processing the energy stored (or to be stored) in the low current reactor at the time of start / stop.

  When the load of this DC power supply is a plasma generator, arcs are frequently generated at the load, so the above start / stop operations frequently occur, making it difficult to start or stop at high speed. May become unstable.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a DC power supply device that is stable in operation at startup.

  Another object of the present invention is to provide a direct current power supply device capable of starting and stopping a load at high speed.

In order to achieve this object, the invention of claim 1 is directed to a chopper circuit for applying a DC voltage pulse obtained by intermittent switching of a main switch element to an inductor and circulating the inductor current with a diode when the main switch element is OFF. An inverter having a full bridge circuit composed of two first to fourth switching elements and converting a DC voltage pulse output from the inductor of the chopper circuit into an AC voltage, and an AC voltage output from the inverter A DC power supply device comprising a voltage conversion circuit that converts a DC voltage into a DC voltage and applies the voltage to a load, wherein the DC voltage pulse pulse output from the main switch element of the chopper circuit after the inverter is activated at startup A control circuit for gradually increasing the width is provided.

  According to a second aspect of the present invention, the control circuit of the DC power supply device stops the operation of the chopper circuit when stopped.

  Furthermore, the control circuit of the DC power supply device according to the invention of claim 3 is characterized in that all of the four first to fourth switching elements are turned on when the DC power supply device is stopped.

According to a fourth aspect of the present invention, the control circuit of the DC power supply device gradually increases the pulse width of the DC voltage pulse output from the main switch element of the chopper circuit after the inverter is operated at the time of startup. The operation of the chopper circuit is stopped at the time of stop, and all the four first to fourth switching elements are turned on.

  According to the first aspect of the present invention, it is possible to stabilize the operation of the DC power supply device and the load at the time of startup. Moreover, according to invention of Claims 2-4, a load can be started and stopped at high speed.

  Embodiments of a DC power supply apparatus according to the present invention will be described below with reference to the drawings.

[First embodiment]
FIG. 1 is a circuit diagram showing a configuration of a DC power supply device 10 used in the plasma generator 1. The DC power supply device 10 includes a rectifier circuit 11, a chopper (chopper circuit) 10A, an inverter 20, and a voltage conversion circuit 10B. The voltage conversion circuit 10B includes a transformer 15 and a rectifier circuit 30.

  In FIG. 1, the rectifier circuit 11 is configured to perform full-wave rectification and smoothing of a three-phase AC voltage. The rectifier circuit 11 includes six diodes D1 to D6 and a capacitor C1.

  Further, the chopper (chopper circuit) 10A includes a main switch element 12, a choke coil (inductor) 13, and a diode 14, and constitutes a current type step-down chopper that functions as a current source.

  The switch element 12 outputs a DC voltage pulse by interrupting the output voltage (DC voltage) of the rectifier circuit 11. The choke coil 13 receives an intermittent DC voltage pulse from the main switch element 12 and operates as a current source. Further, the diode 14 circulates the current by flowing a current (inductor current) to the choke coil 13 when the main switch element 12 is OFF.

  Here, the chopper 10A constitutes a current type step-down chopper, but is not necessarily limited to this, and may constitute a step-up chopper (step-up chopper circuit) or a step-up / step-down chopper (step-up / step-down chopper circuit). .

  Reference numeral 20 denotes an inverter that converts a DC voltage output from the main switch element 12 into an AC voltage. The inverter 20 forms a full bridge circuit including four first to fourth switching elements Q1 to Q4. That is, the first and second switching elements Q1 and Q2 connected in series and the third and fourth switching elements Q3 and Q4 connected in series are connected in parallel.

  Reference numeral 15 denotes a transformer. An alternating voltage output from the inverter 20 is input to the primary side of the transformer 15. A rectifier circuit 30 is connected to the secondary side of the transformer 15.

  The rectifier circuit 30 includes four diodes D7 to D10 that rectify an AC voltage output from the secondary side of the transformer 15, a smoothing capacitor 31 that smoothes the rectified voltage, and a choke coil 32.

Reference numeral 40 denotes a controller for controlling the on / off of the main switch element 12 and the ON / OFF of the first to fourth switching elements Q1 to Q4 of the inverter 20. The controller 40 is in accordance with an input of an operation unit (not shown). And the ON / OFF timing of the first to fourth switching elements Q1 to Q4 is controlled.
[Operation]
Next, the operation of the DC power supply device 10 configured as described above will be described with reference to the time chart shown in FIG.
(1) At start-up The controller 40 first controls the inverter unit 20 at the start-up of the DC power supply device 10, and the switching elements Q1, Q4 and the switching elements Q2, Q3 are alternately turned ON / OFF.

Thereafter, the controller 40 gradually increases the width of the DC voltage pulse output from the main switch element 12 of the chopper 10 </ b> A so as to prevent a large current from flowing to the inverter unit 20.
(2) Control operation by the controller 40 when the output voltage is low When the controller 40 operates an operation unit (not shown) to set the output voltage to “low”, for example, the main switch as shown in FIG. The element 12 is turned on for a period T2 every T1 period.

  By doing so, the switching element 12 is turned ON / OFF, and a DC voltage pulse intermittently applied to the choke coil 13 by the ON / OFF is applied. Along with this, the diode 14 circulates the current by flowing a current (inductor current) to the choke coil 13 when the main switch element 12 is OFF. As a result, the output voltage of the chopper 10A becomes Va as shown in FIG.

  On the other hand, the switching elements Q1, Q4 and switching elements Q2, Q3 of the inverter 20 are alternately turned on and off by the controller 40, and the switching elements Q1, Q4 and switching elements Q2, Q3 are respectively switched by the controller 40 for each Ta cycle. It is turned ON only for Tb period.

  In addition, the period is set to a period in which the switching elements Q1, Q4 and the switching elements Q2, Q3 are simultaneously ON, that is, an overlapping period Tc. This overlapping period Tc is set very short.

  Since the step-down chopper operates in a current type, the inverter 20 is controlled so that a current path is always formed.

  Further, the switching elements Q1 and Q4 and the switching elements Q2 and Q3 of the inverter 20 are alternately turned ON / OFF, whereby an AC voltage having a period Ts is output from the inverter 20 and input to the primary side of the transformer 15. Then, an AC voltage is output to the secondary side of the transformer 15.

  By the way, since the period T2 during which the main switch element 12 is ON is short, the DC voltage input to the inverter 20 is low. That is, the DC voltage output from the rectifier circuit 11 is stepped down to a lower voltage by the step-down chopper.

For this reason, the AC voltage input to the primary side of the transformer 15 is low, and the AC voltage output to the secondary side of the transformer 15 is low. As a result, the DC output voltage output from the rectifier circuit 30 is low.
(3) Control operation by the controller 40 when the output voltage is high When the output voltage is set to “high”, the controller 40 causes the main switch element 12 to switch to T3 (every T3 period) as shown in FIG. T3 >> T2) Control is performed so as to be ON only for the period. Also in this case, it is preferable that the width of the DC voltage pulse output from the main switch element 12 of the chopper 10A is gradually increased so that the main switch element 12 is finally turned on only for the period T3 every T1 period.

  By doing so, the switching element 12 is turned ON / OFF, and a DC voltage pulse intermittently applied to the choke coil 13 by the ON / OFF is applied.

  Along with this, the diode 14 circulates the current by flowing a current (inductor current) to the choke coil 13 when the main switch element 12 is OFF. As a result, the output voltage of the chopper 10A becomes Vb (Vb >> Va) as shown in FIG.

  Then, as shown in FIG. 2B, the switching elements Q1 and Q4 and the switching elements Q2 and Q3 of the inverter 20 are turned on by the controller 40 for a period of Tb every Ta period.

  Moreover, the controller 40 controls ON / OFF of the switching elements Q1 to Q4 so that the period when the switching elements Q1, Q4 and the switching elements Q2, Q3 are simultaneously ON, that is, the overlapping period is Tc. Is done.

  Then, the switching elements Q1 and Q4 and the switching elements Q2 and Q3 of the inverter 20 are alternately turned ON / OFF in this way, whereby an AC voltage having a period Ts is output from the inverter 20 and input to the primary side of the transformer 15. Is done. Then, an AC voltage is output to the secondary side of the transformer 15.

  Here, the control conditions of the switching elements Q1 to Q4 are always constant regardless of the magnitude of the output voltage, and the period T3 during which the main switch element 12 is ON is longer than the period T2 when the output voltage is low. Since the output voltage Vb of the chopper 10A is sufficiently larger than the output voltage Va when the output voltage is low, the AC voltage of the cycle Ts input from the inverter 20 to the primary side of the transformer 15 also increases.

  As a result, the AC voltage output from the secondary side of the transformer 15 becomes larger than that in FIG. 2A, and the DC output voltage output from the rectifier circuit 30 is higher than that in FIG. Become. That is, the output voltage of the rectifier circuit 30 becomes “high”.

  In this way, the DC power supply device 10 can operate smoothly without causing a large current to flow through the inverter unit 20 simply by widening the width of the DC voltage pulse output from the switching element 12 of the chopper 10A.

  In addition, since the boosting amount of the transformer 15 is changed by controlling the overlap period in which the switching elements Q1, Q4 and the switching elements Q2, Q3 of the inverter 20 are simultaneously ON, the number of turns of the transformer 15 Even if the ratio is not increased, the output voltage on the secondary side of the transformer 15 can be increased. For this reason, the turns ratio of the transformer 15 can be reduced, that is, optimized, and the current flowing to the primary side of the transformer 15 when the DC power supply 10 outputs a low voltage can be reduced.

  For this reason, the capacity | capacitance of elements, such as switching element Q1-Q4 connected to the primary side of the transformer 15, may be small, and the inexpensive DC power supply device 10 can be provided.

2A and 2B, an overlap period occurs and the inverter 20 operates as a boost type. However, the influence is slight because the overlap period is short.
(4) Stop operation 1 of DC power supply device 10
Further, when the controller 40 is turned off by an operation of an operation unit (not shown), the controller 40 stops the output of the DC voltage pulse of the main switch element 12 of the chopper 10. In this case, the inverter unit 20 remains operating. It should be noted that power is output to the load until the energy accumulated in the choke coil 13 is released, but since it is very short, there is no problem in the stability of the operation, and the plasma generator (sputtering device) 1 The operation can be stopped immediately.

In this case, since the inverter unit 20 is operating, the operation of the plasma generator 1 can be quickly controlled if the output of the DC voltage pulse of the main switch element 12 of the chopper 10A is started.
(5) Stop operation 2 of DC power supply device 10
However, the DC power supply 10 needs to be stopped rapidly in order to minimize the influence on the plasma generator 1 that is a load when an arc is generated. In order to do this, all the transistors Q1 to Q4 of the inverter unit 20 may be turned on while the chopper 10A is operating. At this time, since the chopper (step-down chopper) 10A operates at a constant current, no overcurrent flows to the inverter unit 20.

Since the chopper 10A is operating, the plasma generator 1 can be restarted quickly and stably by starting the control of the inverter unit 20.
(6) Stop operation 3 of the DC power supply device 10
Thus, high-speed operation control of the plasma generator 1 can be performed by turning off the chopper (step-down chopper) 10A or turning on all the transistors Q1 to Q4 of the inverter unit 20.

  However, even if the chopper (step-down chopper) 10A is turned off and all the transistors Q1 to Q4 of the inverter unit 20 are turned on, the operation of the plasma generator (sputtering device) 1 can be stopped immediately.

  Moreover, after the control of the inverter unit 20 is started, the operation of the chopper 10A is controlled so that the plasma generator 1 can be restarted quickly and stably.

As a result, a high-speed operation is possible, and an optimum power source for plasma generation used in the plasma generator (sputtering apparatus) 1 can be realized.
[Modification 1]
In the embodiment described above, an example in which the chopper 10A is a current type step-down chopper has been shown, but the chopper 10A may be an inversion chopper 10A1 as shown in FIG.

  The inverting chopper 10A1 includes a switch element 12, a diode 14A interposed between the output side of the switch element 12 and the input side of the diode 14, the output side of the switch element 12, the output side of the diode 14, and the choke coil. 13 has a choke coil 13A connected thereto.

In this configuration, only the output of the inverter unit 20 is opposite to that of the above-described embodiment with respect to the output of the switch element 12, and the operation is substantially the same as that of the above-described embodiment. Therefore, even in this configuration, the controller 40 can be set to perform the same control as in the above-described embodiment.
[Modification 2]
Further, although the chopper 10A constitutes a current type step-down chopper, it is not necessarily limited to this, and may be a step-up chopper (step-up chopper circuit) 10A2 as shown in FIG.

  The step-up chopper 10A2 includes a switch element 12, a choke coil 13B, a diode 14B, and a choke coil 13 connected in series between the output side of the rectifier circuit 11 and the input side of the inverter unit 20, and the choke coil 13B. The switching element 12A is connected between the input sides of the diode 14.

  Even in this configuration, the controller 40 can be set to perform the same control as in the above-described embodiment.

  As described above, the DC power supply device 10 according to the embodiment of the present invention applies a DC voltage pulse obtained by intermittent connection of the main switch element 12 to the inductor (choke coil 13), and when the main switch element 12 is OFF. A chopper circuit (10A, 10A1, 10A2) for circulating an inductor (choke coil 13) current through a diode 14 and a full bridge circuit including four first to fourth switching elements Q1 to Q4, and the chopper circuit (10A , 10A1, 10A2) an inverter (inverter unit 20) that converts a DC voltage pulse output from the inductor (choke coil 13) into an AC voltage and outputs the AC voltage, and an AC voltage output from the inverter (inverter unit 20) Is converted into DC voltage and marked on the load (plasma generator 1) And a voltage conversion circuit 10B for.

  In addition, a control circuit (controller 40) is provided that gradually increases the pulse width of the DC voltage pulse output from the chopper circuit (10A, 10A1, 10A2) after operating the inverter (inverter unit 20) at the time of startup. Yes.

  According to this configuration, it is possible to stabilize the operations of the DC power supply device 10 and the load during startup.

  Further, the pulse width of the DC voltage pulse output from the chopper circuit (10A, 10A1, 10A2) is gradually increased after the inverter (inverter unit 20) is operated at start-up, while the chopper circuit (10A , 10A1, 10A2) is provided with a control circuit (controller 40) for stopping the operation.

  According to this configuration, it is possible to start and stop the load at high speed by controlling the operation of the chopper circuit (10A, 10A1, 10A2), and to stabilize the operation of the DC power supply device 10 and the load at the time of startup. .

  The DC power supply device 10 according to the embodiment of the present invention has a pulse width of the DC voltage pulse output from the chopper circuit (10A, 10A1, 10A2) after operating the inverter (inverter unit 20) at the time of start-up. A control circuit (controller 40) is provided that gradually stops the operation of the chopper circuit (10A, 10A1, 10A2) and stops all of the four first to fourth switching elements Q1 to Q4 when stopped. ing.

  According to this configuration, it is possible to start and stop the load at high speed by controlling the first to fourth switching elements Q1 to Q4, and to stabilize the operation of the DC power supply device 10 and the load at the time of startup. .

  Furthermore, in the DC power supply device 10 according to the embodiment of the present invention, the pulse width of the DC voltage pulse output from the chopper circuit (10A, 10A1, 10A2) after operating the inverter (inverter unit 20) at the time of startup. A control circuit (controller 40) is provided that gradually stops the operation of the chopper circuit (10A, 10A1, 10A2) and stops all of the four first to fourth switching elements Q1 to Q4 when stopped. ing.

  According to this configuration, the load can be quickly started and stopped by the operation control of the chopper circuit (10A, 10A1, 10A2) and the operation control of the first to fourth switching elements Q1 to Q4. The operations of the DC power supply device 10 and the load can be stabilized.

It is the circuit diagram which showed the structure of the direct-current power supply device which concerns on this invention. It is the time chart which showed the operation | movement of a DC power supply device. It is the circuit diagram which showed the modification of the DC power supply device of this invention. It is the circuit diagram which showed the further modification of the DC power supply device of this invention.

Explanation of symbols

1 ... Plasma generator (load)
DESCRIPTION OF SYMBOLS 10 ... DC power supply device 12 ... Main switch element 13 ... Choke coil (inductor)
DESCRIPTION OF SYMBOLS 14 ... Diode 10A ... Chopper circuit 10A1 ... Chopper circuit 10A2 ... Chopper circuit Q1-Q4 ... Switching element 20 ... Inverter part (inverter)
10B ... Voltage conversion circuit 40 ... Controller (control circuit)

Claims (4)

A chopper circuit for applying a DC voltage pulse obtained by intermittent switching of the main switch element to the inductor and circulating the inductor current with a diode when the main switch element is OFF, and a full bridge circuit composed of four first to fourth switching elements And an inverter that converts a DC voltage pulse output from the inductor of the chopper circuit into an AC voltage and outputs the AC voltage, and a voltage conversion circuit that converts the AC voltage output from the inverter into a DC voltage and applies it to a load. A DC power supply device comprising:
A DC power supply apparatus comprising: a control circuit that gradually increases a pulse width of the DC voltage pulse output from the main switch element of the chopper circuit after the inverter is operated at the time of startup.   The DC power supply device, wherein the control circuit stops the operation of the chopper circuit when stopped.   The DC power supply device, wherein the control circuit turns on all of the four first to fourth switching elements when stopped. The control circuit gradually increases the pulse width of the DC voltage pulse output from the main switch element of the chopper circuit after operating the inverter at start-up, and stops the operation of the chopper circuit at the time of stop and All the four 1st-4th switching elements are turned ON, The direct-current power supply device characterized by the above-mentioned.

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