DC power source device and pulse generation device

Abstract

To provide a DC power source device and a pulse generation device in which even when a pulse generator successively performs on / off switching operations, unstable operation in control of constant current output of the DC power source device can be prevented and the DC power source device can supply current to the pulse generator without lowering the level of an output current.SOLUTION: A DC power source device includes: a DC voltage output unit that supplies a DC voltage to a pulse generator; an output voltage detection unit 102 that detects the DC voltage; a voltage FB (feedback) compensator that performs constant voltage control for keeping the DC voltage constant on the basis of deviation between a preset voltage set value and the DC voltage; a movement average calculation unit that calculates a movement average value of an output current from the DC voltage output unit to the pulse generator; a current FB feedback compensator that performs constant current output control for calculating a subtraction amount with respect to the voltage set value on the basis of the deviation between the preset current set value and the movement average value and keeping the output current constant; and an addition and subtraction unit 109 that subtracts the subtraction amount from the voltage set value.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a DC power supply device and a pulse generator. [Background technology]

[0002] When a voltage is supplied to a pulse generator from a DC power supply, the current supplied to the pulse generator fluctuates because the pulse generator continuously switches on and off. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-95483 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a DC power supply performs constant current output control (CC control), which suppresses the output voltage when the current limit threshold is exceeded, the output current increases or decreases near the current limit threshold, and the output current is limited each time it exceeds the current limit threshold, resulting in the output voltage value of the DC power supply dropping below the set voltage value.

[0005] The present invention has been made in view of the above, and has an object to provide a DC power supply device and a pulse generator in which unnecessary constant current output control (CC control) is not performed each time the pulse generator is turned on, even when the pulse generator performs continuous on / off switching operations. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the objects, the present invention provides a pulse generator comprising: a DC voltage output unit that supplies a DC voltage to a pulse generator; an output voltage detection unit that detects the DC voltage; a voltage feedback compensator that performs constant voltage control to keep the DC voltage constant based on a deviation between a preset voltage setting value and the DC voltage; a moving average calculation unit that calculates a moving average of an output current from the DC voltage output unit to the pulse generator; a current feedback compensator that calculates a subtraction amount for the voltage setting value based on a deviation between a preset current setting value and the moving average value, thereby performing constant current output control to keep the output current constant; and a subtraction unit that subtracts the subtraction amount from the voltage setting value. [Effects of the Invention]

[0007] The DC power supply device and pulse generator according to the present invention have the advantage of being able to prevent unnecessary constant current output control (CC control) from being performed each time the pulse generator is turned on, even when the pulse generator performs continuous on / off switching operations. [Brief explanation of the drawings]

[0008] [Figure 1A] FIG. 1A is a diagram showing an example of the configuration of a pulse generating device according to this embodiment. [Figure 1B] FIG. 1B is a diagram showing an example of the configuration of a pulse generator according to this embodiment. [Figure 2] FIG. 2 is a diagram for explaining an example of an output current output from a DC power supply device to a pulse generator in a conventional pulse generating device. [Figure 3] FIG. 3 is a diagram showing an example of the configuration of a DC power supply device according to this embodiment. [Figure 4] FIG. 4 is a diagram for explaining an example of an actual DC power supply output current output from the DC power supply device in the pulse generating device according to this embodiment. [Figure 5] FIG. 5 is a diagram for explaining an example of a calculation process of the control amount of the output voltage in the voltage FB compensator included in the DC power supply device according to this embodiment. [Figure 6] FIG. 6 is a diagram for explaining an example of a process for calculating the subtraction amount in the current FB compensator included in the DC power supply device according to this embodiment. [Figure 7] FIG. 7 is a diagram for explaining an example of an actual DC power output current output from the DC power supply device according to this embodiment. [Figure 8] FIG. 8 is a diagram showing an example of a specific configuration of a DC power supply device included in the pulse generating device according to this embodiment. [Figure 9] FIG. 9 is a diagram showing an example of a specific configuration of a DC power supply device included in the pulse generating device according to this embodiment. [Figure 10] FIG. 10 is a diagram for explaining an example of the output conditions of the pulse generating device according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of a DC power supply device and a pulse generator according to the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to these preferred embodiments.

[0010] 1A is a diagram showing an example of the configuration of a pulse generating device according to the present embodiment. The pulse generating device 100 according to the present embodiment is a device that supplies a pulsed voltage to a load (e.g., a plasma load) and controls the output of the pulsed voltage according to preset output conditions (e.g., specified by a voltage value, a pulse frequency, and a duty ratio).

[0011] As shown in FIG. 1A, the pulse generating device 100 according to this embodiment includes a DC power supply 1 and a pulse generator 2. The DC power supply 1 is an example of a DC power supply that converts an AC voltage into a DC voltage and supplies (outputs, applies) it to the pulse generator 2. The DC power supply 1 controls the voltage value among the output conditions described above. The pulse generator 2 is an example of a pulse generator that receives a DC voltage from the DC power supply 1 and performs continuous on-off switching. The pulse generator 2 is configured to output a pulsed voltage by intermittently outputting the DC voltage output from the DC power supply 1. The pulse generator 2 also controls the pulse frequency and duty ratio among the output conditions described above.

[0012] Fig. 1B is a diagram showing an example of the configuration of a pulse generator according to this embodiment. In this embodiment, as shown in Fig. 1B, the pulse generator 2 has a first switching unit 201 and a second switching unit 202. In addition, when the pulse generator 2 is turned on, as shown in Fig. 1B(a), if the output is a positive voltage, the switching element (such as a field effect transistor (FET)) constituting the first switching unit 201 is turned on, and when the output is a negative voltage, as shown in Fig. 1B(b), the switching element (such as a FET) constituting the second switching unit 202 is turned on.

[0013] Furthermore, the continuous on / off switching operation of the pulse generator 2 means that the first switching unit 201 and the second switching unit 202 continuously perform complementary switching operations. For example, when the first switching unit 201 is on, the second switching unit 202 is off, and when the first switching unit 201 is off, the second switching unit 202 is on.

[0014] The fluctuation of the supply current from the DC power supply 1 to the pulse generator 2 means that complementary switching operations are performed, resulting in periods when current flows through the load and periods when current does not flow through the load, and therefore periods when the current value is high and periods when the current value is low are repeated alternately.

[0015] It should be noted here that if the current value of the output current output from the DC power supply 1 to the pulse generator 2 becomes too large, it may damage the switching elements inside the DC power supply 1. For example, immediately after the pulse generator 2 is switched from off to on, a large inrush current flows from the DC power supply 1 to the pulse generator 2. At this time, the charge in the capacitor inside the DC power supply 1 is discharged, and the DC power supply 1 attempts to charge its internal capacitor. As a result, a large current also flows inside the DC power supply 1, and depending on the situation, the switching elements inside the DC power supply 1 may be damaged.

[0016] In order to prevent damage to the switching elements due to such excessive current values, the current value of the output current output from the DC power supply device 1 to the pulse generator 2 is detected, and if the detected current value exceeds a predetermined current threshold, constant current output control (CC control) is performed to reduce the output voltage of the DC power supply device 1 so that the current value of the output current output from the DC power supply device 1 to the pulse generator 2 is equal to or less than the current threshold.

[0017] Fig. 2 is a diagram illustrating an example of an output current output from a DC power supply to a pulse generator in a conventional pulse generating device. In Fig. 2, the vertical axis represents output current (A) and the horizontal axis represents time. When a DC voltage is supplied from the DC power supply 1 to the pulse generator 2, the pulse generator 2 performs continuous on-off switching, causing the output current (actual DC power supply output current) supplied from the DC power supply 1 to the pulse generator 2 to fluctuate.

[0018] Furthermore, when constant current output control (CC control) is performed to suppress the DC voltage from the DC power supply device 1 when the actual DC output current supplied from the DC power supply device 1 exceeds the current threshold, the actual DC output current is limited each time the actual DC output current increases or decreases near the current threshold and exceeds the current threshold, reducing the actual DC output current over one pulse period of the pulsed voltage output by the pulse generator 2. As a result, the average level of the actual DC output current of the DC power supply device 1 falls below the average level of the required DC output current. Here, the required DC output current is the current value required by the pulse generator 2. Specifically, the required DC output current may be the average value of the current required by the pulse generator 2 during its on-period and its off-period. Furthermore, when the actual DC output current falls, the current limiting operation by the constant current output control reduces the preset voltage setting value (see FIG. 3 ), thereby reducing the DC voltage, and the DC voltage input to the pulse generator 2 does not reach the required voltage.

[0019] Even if the pulse generator 2 does not perform continuous on-off switching, i.e., even if the pulse generator 2 remains on after being turned on, constant current output control may be performed to suppress the output current due to the inrush current value when the pulse generator 2 is turned on. In this case, the output voltage of the pulse generator 2 may not reach the desired voltage. This is particularly problematic when the pulse generator 2 performs continuous on-off switching, as the above problem occurs repeatedly. That is, even when only one pulse is turned on, the output current may be reduced by the constant current output control due to the inrush current, resulting in a drop in the DC voltage.

[0020] Furthermore, even when the pulse generator 2 is switched on and off, the output voltage of the DC power supply device 1 drops every time the pulse generator 2 is turned on, which results in a decrease in the DC voltage to the pulse generator 2 and can distort the waveform of the pulses (output waveform) from the pulse generator 2. Note that, for example, if the time for one on-off cycle of the pulse generator 2 is short, the inrush current value decreases from the second cycle onwards, so the above problem does not occur or the degree of the problem is reduced. Also, if the pulse frequency of the pulses generated by the pulse generator 2 is increased, the above problem does not occur or the level of voltage distortion is reduced.

[0021] Therefore, in this embodiment, the DC power supply device 1 prevents unnecessary constant current output control (CC control) from being performed each time the pulse generator 2 is turned on, even when the pulse generator 2 performs continuous on / off switching operations.

[0022] 3 is a diagram showing an example of the configuration of a DC power supply device according to this embodiment. In this embodiment, the DC power supply device 1 includes a DC voltage output unit 101, an output voltage detection unit 102, a voltage FB (feedback) compensator 103, an output current detection unit 104, a moving average calculation unit 105, a current FB (feedback) compensator 106, and addition / subtraction units 107-109.

[0023] The DC voltage output unit 101 is an example of a DC voltage output unit that supplies a DC voltage to the pulse generator 2. The output voltage detection unit 102 is an example of an output voltage detection unit that detects the DC voltage supplied from the DC voltage output unit 101.

[0024] Addition / subtraction unit 108 calculates the deviation between a preset voltage setting value and the DC voltage (output voltage detection value) detected by output voltage detection unit 102. Voltage FB compensator 103 is an example of a voltage feedback compensator that performs constant voltage control to keep the DC voltage constant based on the deviation between a preset voltage setting value and the output voltage detection value.

[0025] The output current detection unit 104 is an example of an output current detection unit that detects the actual DC power supply output current (output current) supplied from the DC voltage output unit 101 to the pulse generator 2. The moving average calculation unit 105 is an example of a moving average calculation unit that calculates a moving average value of the actual DC power supply output current (output current detection value). In this embodiment, the moving average calculation unit 105 calculates the moving average value of the actual DC power supply output current (output current detection value) detected by the output current detection unit 104. In this embodiment, the moving average calculation unit 105 calculates the moving average value of the output current detection value over a moving average time that is set by a user or the like.

[0026] The adding / subtracting unit 109 calculates the deviation between a preset current setting value (also referred to as a CC setting value or current threshold) and a moving average value. The current FB compensator 106 is an example of a current feedback compensator that calculates a subtraction amount for a voltage setting value based on the deviation between a preset current setting value and the moving average value, and performs constant current output control to keep the actual output current of the DC power supply constant.

[0027] The adder / subtractor 107 is an example of a subtractor that subtracts the subtraction amount calculated by the current FB compensator 106 from the voltage setting value.

[0028] Fig. 4 is a diagram for explaining an example of the actual DC power supply output current output from the DC power supply device in the pulse generating device according to this embodiment. In Fig. 4, the vertical axis represents the actual DC power supply output current (A), and the horizontal axis represents time. According to this embodiment, as shown in Fig. 4, it is possible to prevent the average level of the actual DC power supply output current (output current moving average value) from exceeding the current threshold.

[0029] As a result, the DC power supply device 1 can prevent unnecessary constant current output control (CC control) from being performed each time the pulse generator 2 is turned on, even when the pulse generator 2 performs continuous on / off switching operations.

[0030] 5 is a diagram for explaining an example of a calculation process for the control amount of the output voltage in the voltage FB compensator of the DC power supply device according to this embodiment. In this embodiment, the voltage FB compensator 103 may calculate the control amount for performing constant voltage control to keep the DC voltage constant based on the deviation between the voltage setting value and the output voltage detection value, using the calculation formula shown in FIG. 5 and the following formula (1).

number

[0031] 6 is a diagram for explaining an example of a process for calculating the subtraction amount in the current FB compensator included in the DC power supply device according to this embodiment. In this embodiment, the current FB compensator 106 may calculate the subtraction amount for the voltage set value based on the deviation between the current set value and the moving average value using the calculation formula shown in FIG. 6 and the following formula (2). Also, in this embodiment, the current FB compensator 106 calculates the subtraction amount only when the output current detection value (actual output current of the DC power supply) is greater than the CC set value.

number

[0032] FIG. 7 is a diagram illustrating an example of the actual DC power supply output current output from the DC power supply device according to this embodiment. In FIG. 7, the vertical axis represents the actual DC power supply output current and the average level of the actual DC power supply output current, and the horizontal axis represents time. As shown in FIG. 7, by calculating a subtraction amount based on the deviation between the moving average value of the actual DC power supply output current and the CC set value in the current FB compensator 106, it can be seen that the actual DC power supply output current output from the DC voltage output unit 101 and its average level do not decrease. It can also be seen that the CC control in the current FB compensator 106 does not operate unstable, so the current waveform of the actual DC power supply output current does not collapse.

[0033] 8 and 9 are diagrams showing an example of a specific configuration of a DC power supply device included in a pulse generator according to this embodiment. In this embodiment, the DC power supply device 1 includes an AC rectifier / smoothing circuit for AC input voltage, a step-up chopper circuit 801, a step-down chopper circuit 802, a full-bridge converter 803 including a resonant circuit, a transformer isolation unit 804, and a voltage doubler circuit 805. In this embodiment, the DC power supply device 1 uses two units, from the AC rectifier / smoothing circuit to the step-down chopper circuit 802, each of whose outputs is connected to the full-bridge converter 803. Each unit is connected in four parallel configurations to the transformer isolation unit 804, and each is connected to a voltage doubler circuit 805. The four voltage doubler circuits 805 are connected in series. Since there are two units in each unit, the voltage doubler circuits 805 are connected in eight series configurations to their output terminals.

[0034] The DC power supply 1 also has an overcurrent protection function, such as the constant current output control (CC control) described above, to prevent damage to equipment due to overcurrent. The overcurrent protection function protects switching elements such as FETs. A long-term flow of overcurrent through a switching element such as an FET can lead to overheating and damage. A typical overcurrent protection function reduces the DC voltage when the output current detection value at the output terminal of the DC power supply 1 exceeds a predetermined current threshold, thereby reducing the actual output current of the DC power supply. This type of control poses a problem: the DC voltage is reduced by the overcurrent protection function, making it impossible to obtain the desired DC voltage. In particular, when a pulsed voltage is repeatedly output from the pulse generator 2, the above problem is repeated, preventing proper processing at the load.

[0035] Therefore, this embodiment is characterized in that overcurrent protection is performed when the moving average value of the output current detection value at the output terminal of the DC power supply device 1 exceeds a preset current threshold. Since the moving average value conditions and the current threshold value differ depending on the output conditions (defined by the voltage value, pulse frequency, and duty ratio), it is preferable to determine and set optimal values through experiments or simulations.

[0036] Fig. 10 is a diagram illustrating an example of the output conditions of the pulse generator according to this embodiment. The output conditions of the pulse generator 100 may be, for example, a voltage value of 10 kV, a pulse frequency of 400 kHz, and a duty ratio of 0.5. The pulse waveform shown in Fig. 10 is an example of a pulse waveform generated under output conditions in which pulses of the above output conditions are repeatedly turned on and off (operating and non-operating) at a cycle of 100 Hz.

[0037] According to the DC power supply device 1 (or pulse generator 100) of this embodiment, a moving average value of the current value of the actual output current of the DC power supply is calculated, and a decision is made on whether to perform constant current output control (CC control) based on this moving average value. Therefore, even when a momentarily large current value flows, such as an inrush current when the pulse generator 2 is turned on, it is possible to prevent unnecessary constant current output control (CC control) from being performed.

[0038] Furthermore, when the pulse generator 2 is continuously switched on and off, and the output voltage of the pulse generator 2 becomes a pulsed voltage, it is possible to prevent unnecessary constant current output control (CC control) from being performed each time the pulse generator 2 is turned on. As a result, it is possible to prevent unnecessary voltage drops from occurring relative to the voltage setting value set in the DC power supply device 1.

[0039] Of course, the moving average value is smaller than the instantaneous value of the actual DC power supply output current, so the moving average time used to calculate the moving average value should not be set longer than necessary. Therefore, it is necessary to determine the conditions for the moving average value, such as the moving average time, taking into consideration the output conditions of the pulse generator 100. Variation 1

[0040] This modification is an example in which the subtraction amount is calculated using a moving average value according to the frequency of pulses from the pulse generator 2. In the following explanation, explanation of the same configuration as in the above-mentioned embodiment will be omitted.

[0041] In this modification, pulse frequency information is passed from the pulse generator 2 to the DC power supply device 1, whereby an appropriate moving average value is calculated and the moving average value of the DC power supply is automatically set. Specifically, the DC power supply device 1 further includes a storage unit that stores the pulse frequency of pulses generated by the pulse generator 2 and a moving average time used to calculate the moving average value of the current value of the actual output current of the DC power supply, in association with each other. The moving average calculation unit 105 then reads out from the storage unit the moving average time corresponding to the pulse frequency information notified by the pulse generator 2, and calculates the moving average value of the current value of the actual output current of the DC power supply using the read moving average time. [Explanation of symbols]

[0042] 1 DC power supply 2 Pulse Generator 101 DC voltage output section 102 Output voltage detection section 103 Voltage FC Compensator 104 Output current detection section 105 Moving average calculation section 106 Current FB compensator 107, 108, 109 Addition and subtraction section 201 First Switching Section 202 Second Switching Section 801 Boost chopper circuit 802 Step-down chopper circuit 803 Full Bridge Converter 804 Transformer insulation section 805 voltage multiplier circuit

Claims

1. a DC voltage output section that supplies a DC voltage to the pulse generator; an output voltage detection unit that detects the DC voltage; a voltage feedback compensator that performs constant voltage control to keep the DC voltage constant based on a deviation between a preset voltage setting value and the DC voltage; a moving average calculation unit that calculates a moving average value of an output current from the DC voltage output unit to the pulse generator; a current feedback compensator that calculates a subtraction amount for the voltage setting value based on a deviation between a preset current setting value and the moving average value, and performs constant current output control to keep the output current constant; a subtraction unit that subtracts the subtraction amount from the voltage setting value; A DC power supply device comprising:

2. further comprising an output current detection unit that detects the output current; 2. The DC power supply device according to claim 1, wherein said moving average calculation section calculates said moving average value of said output current detected by said output current detection section.

3. a memory unit that stores a pulse frequency of the pulses generated by the pulse generator and a moving average time used to calculate the moving average value, in association with each other; 2. The DC power supply device according to claim 1, wherein said moving average calculation unit reads out said moving average time corresponding to said pulse frequency from said storage unit and calculates said moving average value.

4. a pulse generator; a DC voltage output unit that supplies a DC voltage to the pulse generator; an output voltage detection unit that detects the DC voltage; a voltage feedback compensator that performs constant voltage control to keep the DC voltage constant based on a deviation between a preset voltage setting value and the DC voltage; a moving average calculation unit that calculates a moving average value of an output current from the DC voltage output unit to the pulse generator; a current feedback compensator that calculates a subtraction amount for the voltage setting value based on a deviation between a preset current setting value and the moving average value, and performs constant current output control to keep the output current constant; a subtraction unit that subtracts the subtraction amount from the voltage setting value; A pulse generator comprising:

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