JP2004303707A - Method and apparatus for adjusting resonance point in high-voltage circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adjusting method and an adjusting apparatus of a resonance point in a high-frequency transformer capable of automatically coping with variations in a resonance point caused by temperature change, or the like, and hence securing stable feedback control. <P>SOLUTION: The adjusting apparatus 10 of the resonance point is used for adjusting parallel resonance composed of a Cockcroft-Walton-type multiplication circuit having distribution capacity Cs and the distribution capacity Cs of a high-voltage circuit equipped with a step-up transformer having a mutual inductance Lex, and the mutual inductance Lex. The adjusting apparatus 10 comprises a phase difference detection means 14 for detecting the phase difference between a momentary voltage and a momentary current from the primary side of the step-up transformer; a transformer 16 for resonance point adjustment connected to the step-up transformer in parallel; and an excitation current control means 18 for supplying an excitation current to the transformer 16 for resonance point adjustment so that the phase difference is reduced corresponding to the size of phase difference detected by the phase difference detection means 14. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for adjusting a resonance point of a high-voltage circuit, and more particularly to a method and an apparatus for adjusting a resonance point of a high-voltage circuit used for an electron beam acceleration power supply such as an electron gun.
[0002]
[Prior art]
In an electron beam type writing apparatus, a high-output high-voltage power supply is used for accelerating an electron beam. As such a power supply, for example, as disclosed in Patent Literature 1, a high voltage circuit combining a Cockcroft-Walton type (hereinafter abbreviated as CW) frequency multiplier circuit and a step-up transformer is used. .
[0003]
FIG. 6 shows an example of this type of high-voltage circuit. In FIG. 6, reference numeral 1 denotes a CW frequency multiplier, and 2 denotes a step-up transformer. Such a high-voltage circuit is used for high-frequency driving in order to reduce the size and reduce the ripple voltage and the internal resistance.
[0004]
By the way, in the high voltage circuit in which the CW multiplying circuit 1 and the step-up transformer 2 are combined, as shown in FIG. 8, the CW multiplying circuit 1 has a distributed capacitance Cs between columns. The distributed capacitance Cs is connected in parallel with the mutual inductance Lex of the step-up transformer 2.
[0005]
In the equivalent circuit shown in FIG. 7, L11 is the primary inductance of the step-up transformer 2, L12 is the secondary inductance of the transformer 2, and Lex is the mutual inductance of the transformer 2.
[0006]
In such an equivalent circuit, when driving at a high frequency, it is desirable that the phases of the voltage and the current are matched. Therefore, usually, the mutual inductance Lex of the step-up transformer and the distributed capacitance Cs are caused to resonate in parallel, so that the voltage and the current Are matched.
[0007]
In this case, the distribution capacitance Cs cannot be changed to obtain a desired driving frequency (same as the parallel resonance frequency of the mutual inductance Lex and the distributed capacitance Cs). Therefore, generally, the mutual inductance Lex of the step-up transformer 2 is generally not changed. Conventionally, when changing the inductance Lex, as shown in FIG. 8, a spacer is interposed in a divided portion of the transformer core of the step-up transformer 2 to adjust the gap. Was.
[0008]
However, such a conventional method of adjusting the resonance point of a high-frequency transformer has the following technical problems.
[0009]
[Patent Document 1]
JP 2001-351799 A
[Problems to be solved by the invention]
That is, in the method of adjusting the resonance frequency by adjusting the gap of the step-up transformer 2 shown in FIG. 8, it is difficult to finely adjust the resonance point, and the magnetic permeability of the transformer core used for the step-up transformer 2 is difficult. Varies with the ambient temperature, and when the magnetic permeability changes, the resonance point is also slightly displaced, but in such a case, it has been almost impossible to cope with this by adjusting the gap.
[0011]
Further, in the high voltage circuit shown in FIG. 6, in order to make the output voltage of the CW multiplication circuit 1 constant, a resistor voltage divider 3 and a comparator 4 are provided as shown in FIG. The variable output DC power supply 6 supplied to the step-up transformer 2 was subjected to negative feedback control.
[0012]
The outline of the control at this time is as follows. The output voltage of the CW multiplying circuit 1 is detected by the resistor voltage divider 3, inputted to the comparator 4, compared with the reference voltage signal, and controlled according to the state of the output voltage. The signal is sent to the variable output DC power supply 6.
[0013]
In this case, since the switching frequency of the inverter circuit 5 is normally fixed, if the exciting inductance of the step-up transformer 2 fluctuates due to a temperature change, the parallel resonance point with the distributed capacitance Cs of the CW multiplication circuit 1 changes. In some cases, the phase of the current is advanced from the phase of the voltage.
[0014]
In such a state, the high-voltage control system that is negatively feedback-controlled via the voltage divider 3 and the comparator 4 has a problem that the oscillation is almost stopped and stable control cannot be expected.
[0015]
The present invention has been made in view of such conventional problems, and an object thereof is to automatically respond to a change in a resonance point due to a temperature change or the like. As a result, it is an object of the present invention to provide a method and an apparatus for adjusting a resonance point of a high-frequency transformer capable of ensuring stable feedback control.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, the present invention relates to a Cockcroft-Walton type multiplier having a distributed capacitance Cs, and a step-up transformer having a mutual inductance Lex, wherein the distributed capacitance Cs and the mutual inductance Lex are used. In the method for adjusting the resonance point of the parallel resonance to be configured, a phase difference between an instantaneous voltage and an instantaneous current is detected from a primary side of the step-up transformer, and an exciting current of a resonance point adjusting transformer connected in parallel to the step-up transformer is detected. In accordance with the magnitude of the detected phase difference, the phase difference is supplied so as to be reduced.
[0017]
Further, the present invention provides a high-frequency circuit including a Cockcroft-Walton-type multiplier circuit having a distributed capacitance Cs and a step-up transformer having a mutual inductance Lex, wherein a parallel resonance resonance comprising the distributed capacitance Cs and the mutual inductance Lex is provided. In the point adjusting device, a phase difference detecting means for detecting a phase difference between an instantaneous voltage and an instantaneous current from a primary side of the step-up transformer; a resonance point adjusting transformer connected in parallel to the step-up transformer; Excitation current control means for supplying an excitation current to the resonance point adjusting transformer so as to reduce the phase difference in accordance with the magnitude of the phase difference detected by the detection means.
[0018]
According to the method and the apparatus for adjusting the resonance point of the high-voltage circuit thus configured, the phase difference between the instantaneous voltage and the instantaneous current is detected from the primary side of the step-up transformer, and the resonance point adjustment connected in parallel to the step-up transformer The excitation current of the transformer is supplied in accordance with the magnitude of the detected phase difference so that the phase difference is reduced, so that the instantaneous voltage and the instantaneous current supplied to the step-up transformer are automatically adjusted. The phase difference can be matched.
[0019]
In this case, the phase difference between the instantaneous voltage and the instantaneous current supplied to the step-up transformer occurs, for example, when the magnetic permeability of the transformer core changes due to the ambient temperature. Although the point is also slightly displaced, in the present invention, since the adjustment is made so as to reduce the generated phase difference, the adjustment of the resonance point of the parallel resonance is automatically performed as a result.
[0020]
In addition, if the phase difference between the instantaneous voltage and the instantaneous current supplied to the step-up transformer can be matched, the high-voltage control system under negative feedback control does not become oscillating and can perform stable control. .
[0021]
The phase difference detecting means detects a zero-cross point between the instantaneous voltage and the instantaneous current taken out from the primary side of the step-up transformer, and converts the instantaneous voltage and current pulse signal into a voltage and a current pulse signal having a width corresponding to the detected zero-cross point. Receiving the voltage and current pulse signals transmitted from the zero cross detector, detecting a phase difference between the voltage and current pulse signals, and transmitting a pulse signal corresponding to the phase difference. And a phase difference detector.
[0022]
A first phase difference detector for detecting a phase difference between the voltage and the current pulse signal when the current pulse signal has a leading phase than the voltage pulse signal; A second phase difference detector for detecting a phase difference when the signal has a phase delayed from the voltage pulse signal may be provided.
[0023]
The resonance point adjusting transformer can be offset so that an operating point by the exciting current is near magnetic saturation.
[0024]
The inductance given to the step-up transformer by offsetting the resonance point adjusting transformer can be set to about 100 times the mutual inductance Lex.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1 to 5 show an embodiment of a method and an apparatus for adjusting a resonance point of a high-voltage circuit according to the present invention.
[0026]
FIG. 1 is a circuit diagram showing the overall configuration of the adjustment device 10. The high-voltage circuit whose resonance point is to be adjusted is the same circuit as that shown in FIG. 6, and includes a CW multiplication circuit 1 and a step-up transformer. 2 is combined.
[0027]
FIG. 1 shows an equivalent circuit of the high-voltage circuit having such a configuration. The distributed capacitance Cs exists between the columns of the CW multiplier circuit 1. L11 is the primary inductance of the step-up transformer 2, and L12 is Is the secondary inductance of the transformer 2, and Lex is the mutual inductance of the transformer 2.
[0028]
Such a high-voltage circuit is driven by a high-frequency power supply 12. The high-frequency power supply 12 shown in FIG. 1 converts the output voltage of the inverter circuit 5 or the CW multiplication circuit 1 shown in FIG. It includes a negative feedback control system such as a resistance voltage divider 3 and a comparator 4 used for making the voltage constant.
[0029]
The resonance point adjusting device 10 according to the present embodiment includes a phase difference detecting unit 14, a resonance point adjusting transformer 16, and an exciting current control unit 18. The phase difference detecting means 14 detects a phase difference between the instantaneous voltage v supplied to the transformer 2 and the instantaneous current i from the primary side of the step-up transformer 2 and includes a zero-cross detector 14a, A first phase difference detector 14b and a second phase difference detector 14c are provided.
[0030]
The zero-cross detector 14a has two input terminals. One input terminal is connected to the primary coil side of the step-up transformer 2 to receive the instantaneous voltage v, and the other input terminal is connected to the current transformer CT. The instantaneous current i is input via the current transformer CT.
[0031]
The zero-cross detector 14a receives the instantaneous voltage v and the instantaneous current i, detects a zero-cross point of each instantaneous voltage v or instantaneous current i, and outputs the voltage pulse signal Vp and the current as shown in FIG. And a pulse signal Ip.
[0032]
In this case, the interval between the detected zero-cross points of each pulse signal Vp, Ip is the pulse width of each pulse signal Vp, Ip. The first and second phase difference detectors 14b and 14c receive the voltage and current pulse signals Vp and Ip sent from the zero-cross detector 14a, and detect the phase difference between the voltage and current pulse signals Vp and Ip. The pulse signals a1, a2, b1, and b2 corresponding to the phase difference are transmitted.
[0033]
In the case of this embodiment, the first and second phase difference detectors 14b and 14c are composed of a flip-flop circuit and an amplifier, and the flip-flop circuit of the first phase difference detector 14b has a current pulse at the D terminal. The signal Ip is input via the amplifier A1, and the voltage pulse signal Vp is input to the clock terminal.
[0034]
In the flip-flop circuit of the second phase difference detector 14c, the voltage pulse signal Vp is input to the D terminal via the amplifier A2, and the current pulse signal Ip is input to the clock terminal.
[0035]
The flip-flop circuit of the first phase difference detector 14b operates between the voltage and current pulse signals Vp and Ip when the current pulse signal Ip has a phase advanced from the voltage pulse signal Vp, as shown in FIG. An output signal a1 is sent from the Q terminal between the rise of the voltage pulse signal Vp and the fall of the current pulse signal Ip, and the output signal a1 varies depending on the phase difference between the voltage and the current pulse signals Vp and Ip. Pulse width.
[0036]
In this case, the flip-flop circuit of the second phase difference detector 14c does not operate, and the output signal b1 becomes zero level. As shown in FIG. 4, the flip-flop circuit of the second phase difference detector 14b operates between the voltage and current pulse signals Vp and Ip when the current pulse signal Ip has a later phase than the voltage pulse signal Vp. An output signal b2 is sent out from the Q terminal between the rise of the current pulse signal Ip and the fall of the voltage pulse signal Vp, and the output signal b2 depends on the phase difference between the voltage and the current pulse signals Vp and Ip. Pulse width.
[0037]
In this case, the flip-flop circuit of the first phase difference detector 14c does not operate, and the output signal a2 becomes zero level. The resonance point adjusting transformer 16 includes a primary coil 16a and a secondary coil 16b.
[0038]
One end of the primary coil 16a is grounded, and the other end of the primary coil 16a is connected to an output transistor Q constituting a part of the exciting current control means 18 described later. The secondary coil 16b is connected in parallel with the mutual inductance Lex of the step-up transformer 2. Specifically, the primary coil of the step-up transformer 2 and the secondary coil 16b of the resonance point adjusting transformer 16 are connected in parallel.
[0039]
When there is a phase difference between the voltage and the current pulse signals Vp and Ip, the exciting current control means 18 changes the exciting current of the resonance point adjusting transformer 16 so that the phases between the voltage and the current pulse signals Vp and Ip match. Is controlled as follows.
[0040]
In the case of the present embodiment, a pair of switching transistors Q2 and Q4, an offset voltage generator 18a, a + correction voltage generator 18b, a -correction voltage generator 18c, an output transistor Q, and a plurality of amplifiers A3 to A5. It is schematically configured.
[0041]
The offset voltage generating unit 18a sends out a DC voltage Vo of a predetermined magnitude, and its output side is connected to the gate of the output transistor Q via an amplifier A5, and an exciting current of a predetermined magnitude is always used for adjusting the resonance point. The power is supplied to the primary coil 16a of the transformer 16.
[0042]
In this case, the exciting current is offset so that the operating point A due to the exciting current of the transformer 16 is near the magnetic saturation point, as shown by the BH curve of the resonance point adjusting transformer 16 in FIG.
[0043]
In this case, the inductance given to the step-up transformer 2 is, for example, about 100 times the mutual inductance Lex. When the size is set to such a value, since the applied inductance is connected in parallel, the mutual inductance Lex is affected only by 1%.
[0044]
The switching transistor Q2 is interposed on the output side of the + correction voltage generator 18b, is connected to the output side of the offset voltage generator 18a via an amplifier A3, and has a gate connected to the first phase difference detector 14a. The output side of the flip-flop circuit is connected. The + correction voltage generator 18b always sends a positive voltage V + of a predetermined magnitude.
[0045]
The switching transistor Q4 is interposed on the output side of the -correction voltage generator 18c, is connected to the output side of the offset voltage generator 18a via an amplifier A4, and has a gate connected to the second phase difference detector 14c. The output side of the flip-flop circuit is connected. The correction voltage generator 18c constantly sends a negative voltage V- of a predetermined magnitude.
[0046]
In the resonance point adjusting device 10 configured as described above, for example, if the resonance point of the parallel resonance formed by the mutual inductance Lex and the distributed capacitance Cs of the step-up transformer 2 changes due to a temperature rise or the like, this change is made. , Appears as a phase difference between the instantaneous voltage v and the instantaneous current i.
[0047]
Such a phase difference is detected by the first phase difference detector 14a, as shown in FIG. 3, when the instantaneous current i has a later phase than the instantaneous voltage v, for example. Then, the pulse signal is sent to the switching transistor Q2 as a pulse signal a1 having a width corresponding to the detected phase difference.
[0048]
The transistor Q2 that has received the pulse signal a1 is turned on while the signal a1 is being transmitted, and accordingly, the output voltage V + of the + correction voltage generation unit 18b changes to the output voltage of the offset voltage generation unit 18a. Sent to the side.
[0049]
As a result, a voltage (Vo + V +) obtained by adding the output voltage V + of the correction voltage generator 18b to the output voltage value Vo of the offset voltage generator 18a is applied to the output transistor Q. Since the excitation is performed with the excitation current corresponding to the voltage, the operating point on the BH curve shown in FIG. 5 moves to the right.
[0050]
That is, when the instantaneous current i is in a phase delayed from the instantaneous voltage v, the offset operating point A is displaced to the left from an appropriate position, and the operating point is shifted to the right from this state. , The exciting current is increased.
[0051]
Then, when the phase difference between the instantaneous current i and the instantaneous voltage v is detected after the elapse of a predetermined time, if the instantaneous current i is still in a phase delayed from the instantaneous voltage v, the above-described operation is repeated.
[0052]
At this time, since the resonance point is once adjusted, the phase difference between the instantaneous current i and the instantaneous voltage v is reduced, and the switching transistor Q2 is turned on in a shorter time than the previous time. The resonance point adjusting transformer 16 moves the operating point on the BH curve shown in FIG. 5 further to the right, and repeats such operations a plurality of times. The resonance point coincides with the resonance point of the parallel resonance constituted by the mutual inductance Lex of the transformer 2 and the distributed capacitance Cs.
[0053]
When the instantaneous current i is in a phase advanced from the instantaneous voltage v, the phase difference is detected by the second phase difference detector 14c and the operation is substantially the same as in the case of the advance phase. Is repeated to adjust the resonance point.
[0054]
According to the method and the apparatus for adjusting the resonance point of the high-voltage circuit configured as described above, the phase difference between the instantaneous voltage v and the instantaneous current i is detected from the primary side of the step-up transformer 2, and The exciting current of the resonance point adjusting transformer 16 connected in parallel is supplied so as to reduce the phase difference in accordance with the magnitude of the detected phase difference. The phase difference between the supplied instantaneous voltage v and instantaneous current i can be matched.
[0055]
In this case, the phase difference between the instantaneous voltage v and the instantaneous current i supplied to the step-up transformer 2 occurs, for example, when the magnetic permeability of the transformer core changes due to the ambient temperature, and the magnetic permeability changes accordingly. As a result, the resonance point is slightly displaced, but in this embodiment, since the adjustment is performed so as to eliminate the phase difference, the resonance point of the parallel resonance is automatically adjusted as a result.
[0056]
If the instantaneous voltage v supplied to the step-up transformer 2 and the instantaneous current i can be made to have the same phase difference, the high-voltage control system under negative feedback control does not become oscillating and becomes stable. Control can be performed.
[0057]
Further, in the case of the present embodiment, the phase difference detector detects the phase difference between the voltage and current pulse signals Vp and Ip when the current pulse signal Ip has a later phase than the voltage pulse signal Vp. A first phase difference detector 14b and a second phase difference detector 14c for detecting a phase difference when the current pulse signal IP has a phase advanced from the voltage pulse signal Vp are provided.
[0058]
For this reason, it is possible to automatically cope with a case where the resonance point is displaced in any of the positive and negative directions.
[0059]
【The invention's effect】
As described in detail above, according to the method and the apparatus for adjusting the resonance point according to the present invention, it is possible to automatically respond to the fluctuation of the resonance point due to a temperature change or the like. Feedback control can be ensured.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of an overall configuration showing an embodiment of a resonance point adjusting device according to the present invention.
FIG. 2 is a waveform diagram of input / output signals of the zero-cross detector shown in FIG.
FIG. 3 is a waveform diagram of input / output signals of a first phase difference detector shown in FIG. 1;
FIG. 4 is a waveform diagram of input / output signals of the second phase difference detector shown in FIG.
FIG. 5 is an explanatory diagram of an operating point of the resonance point adjusting transformer shown in FIG. 1;
FIG. 6 is a circuit diagram of a high-voltage circuit to which the present invention is applied.
FIG. 7 is an equivalent circuit diagram of a main part of the high-voltage circuit of FIG. 6;
FIG. 8 is an explanatory diagram of a conventional method of adjusting a resonance point.
[Explanation of symbols]
REFERENCE SIGNS LIST 10 resonance point adjustment device 12 high frequency power supply 14 phase difference detection means 16 resonance point adjustment transformer 18 excitation current control means

Claims (6)

In a method for adjusting a resonance point of a parallel resonance configured by the distributed capacitance Cs and the mutual inductance Lex in a high voltage circuit including a Cockcroft-Walton type multiplier circuit having a distributed capacitance Cs and a step-up transformer having a mutual inductance Lex,
Detecting the phase difference between the instantaneous voltage and the instantaneous current from the primary side of the step-up transformer,
A step of supplying an exciting current of a resonance point adjusting transformer connected in parallel to the step-up transformer so as to reduce the phase difference in accordance with the magnitude of the detected phase difference. How to adjust the resonance point of the circuit. In a high-frequency circuit including a Cockcroft-Walton type multiplier circuit having a distributed capacitance Cs and a step-up transformer having a mutual inductance Lex, in a device for adjusting a resonance point of a parallel resonance comprising the distributed capacitance Cs and a mutual inductance Lex,
Phase difference detection means for detecting the phase difference between the instantaneous voltage and the instantaneous current from the primary side of the step-up transformer,
A resonance point adjusting transformer connected in parallel to the step-up transformer,
Excitation current control means for supplying an excitation current to the resonance point adjusting transformer so as to reduce the phase difference in accordance with the magnitude of the phase difference detected by the phase difference detection means. An apparatus for adjusting a resonance point of a high voltage circuit. The phase difference detecting means detects a zero-cross point between an instantaneous voltage and an instantaneous current taken out from the primary side of the step-up transformer, and converts it into a voltage / current pulse signal having a width corresponding to the width between the detected zero-cross points. A zero-cross detector
A phase difference detector that receives the voltage and current pulse signals sent from the zero-cross detector, detects a phase difference between the voltage and current pulse signals, and sends a pulse signal corresponding to the phase difference. 3. The apparatus for adjusting a resonance point of a high-voltage circuit according to claim 2, wherein A first phase difference detector that detects a phase difference between the voltage and the current pulse signal when the current pulse signal has a leading phase than the voltage pulse signal;
3. The adjustment of the resonance point of the high-voltage circuit according to claim 2, further comprising a second phase difference detector that detects a phase difference when the current pulse signal has a phase delayed from the voltage pulse signal. apparatus. The resonance point adjustment of the high voltage circuit according to any one of claims 1 to 4, wherein the resonance point adjustment transformer is offset so that an operating point by the excitation current is near magnetic saturation. apparatus. 6. The apparatus for adjusting a resonance point of a high-voltage circuit according to claim 5, wherein an inductance given to the step-up transformer by offsetting the resonance point adjustment transformer is set to about 100 times the mutual inductance Lex.

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