JPH0731149A - High dc voltage generating circuit - Google Patents

Abstract

PURPOSE:To obtain a circuit for generating high DC voltage efficiently using a multistage voltage doubler rectifier circuit. CONSTITUTION:The high DC voltage generating circuit comprises high frequency power supplies 1, 3, 5, first series of diodes 7,..., 59, second series of diodes 9,..., 61, and third series of diodes 11,...,63. The even numbered joints of respective series of diode are connected in common with one ends of a group of smoothing capacitors 25, 45, 65 having the other grounded ends. The odd numbered joints of respective series of diodes are connected with one ends of a group of boost capacitors 25, 45, 65 having the other ends connected with high frequency power supplies 1, 3, 5. With regard to the voltage doubler rectifier function, each phase of the high frequency power supplies 1, 3, 5 is boosted independently and power is fed in parallel to the group of smoothing capacitors 25, 45, 65. This constitution allows efficient boosting while suppressing the voltage fluctuation rate even when the number of stages is large.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC high voltage generator, and more particularly to a DC high voltage generator having a multi-phase AC input and comprising a multi-stage voltage doubler rectifying circuit composed of a plurality of capacitors and diodes. .

[0002]

2. Description of the Related Art As a power source for a device requiring a DC high voltage of ultrahigh voltage such as a particle accelerator, a DC high voltage generator composed of a multistage voltage doubler rectifying circuit composed of a plurality of capacitors and diodes is used. It is used. A circuit of this type of DC high voltage generator is, for example,
45-39775. FIG. 2 shows the circuit, in which a so-called Cockcroft circuit is driven by three-phase AC. When this circuit is configured in multiple stages, the capacitors are connected in series with each other, and the rectified DC energy is sequentially transmitted to the upper stage in series, so as it progresses to the upper stage, it is charged by the stray capacitance. The voltage tends to decrease. Therefore, in the above publication, connecting a compensation coil is proposed as a solution for reducing the charging voltage.

[0003]

However, in such a conventional circuit, when the number of constituent stages increases, the number of compensation coils also increases in accordance with the number of stages, and the device including the insulation treatment is It gets complicated. In addition, due to the floating capacitance, there is a limit to the boosting rate toward the upper stage, and even if the number of stages is increased, the upper limit of the output voltage may appear. Furthermore, because the boosting mechanism is a structure that pumps up from the bottom up, the stored energy in the upper stage decreases, and there is a problem that the overall voltage fluctuation rate deteriorates.

An object of the present invention is to obtain a DC high voltage generator using a voltage doubler rectifier circuit having a multi-stage configuration, which has a simple configuration and a good voltage fluctuation rate and which can efficiently boost the voltage. .

[0005]

The present invention proposes the following means in order to solve this problem. N-phase high-frequency power source connection terminal whose neutral point is connected to the reference potential point; and n sets of diode rows each having one end connected to the reference potential point and 2m-stage diodes connected in series in the same direction A branch group of push-up capacitors in which one end of m capacitor means connected to each high-frequency power supply connection terminal is commonly connected; and m capacitor means each having one end connected to the reference potential point And a smoothing capacitor group. The even-numbered connection points of each diode string are connected in common and connected to the terminals of the smoothing capacitor branch group, and the odd-numbered connection points of the diode string of each phase are respectively connected to the boost capacitor branch group of each phase. We propose to obtain a DC high-voltage output from the terminals of the smoothing capacitor branch group by connecting to the terminals of.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a DC high voltage generator according to the present invention will be described. In the figure, the first phase high frequency power source 1,
The second-phase high-frequency power supply 3 and the third-phase high-frequency power supply 5 are inverter-based high-frequency power supplies with a frequency of 100 kHz and a voltage peak value e = 50 kV, and their phases are shifted by 120 degrees. It is an exchange. These high frequency power sources 1, 3 and 5 are between terminals 2 and 8, between terminals 4 and 10,
It is connected between terminals 6 and 12, of which terminals 2, 4,
6 are commonly connected and connected to the ground point 14. It is a three-phase star connection, so to speak. The voltage doubler rectifier circuit according to the present invention is composed of a diode string group, a smoothing capacitor branch group, and a boosting capacitor branch group, and is sequentially rectified and boosted for each stage, between the terminals of the smoothing capacitor at the final stage. The DC high voltage output is obtained in the number of stages of the peak-to-peak voltage of the high frequency power source.

First, regarding the configuration of the diode array group, the diodes 7, 19, 27, 39, 47 and 59 are connected in series in one direction to each other to form a first diode array. Similarly, a second diode array including diodes 9, 21, 29, 41, 49, 61 and a third diode array including diodes 11, 23, 31, 43, 51, 63 are formed. The anodes of the diodes 7, 9, 11 which are the starting points of these three sets of diode arrays are commonly connected and connected to the ground point 14.

Next, the smoothing capacitor branch group will be described. Second connection point of the first, second, and third diode rows (connection point between cathode of diode 19 and anode of diode 27, connection point between cathode of diode 21 and anode of diode 29, cathode of diode 23) And a connection point between the anode of the diode 31) and the anode of the diode 31 are commonly connected to one end of the capacitor 25. This capacitor 25
The other end of is connected to the ground point 14.

Next, 4 of the first, second and third diode rows
The second connection point (cathode of diode 39 and diode 47
Connection point between the cathode of the diode 41 and the anode of the diode 49, and the connection point between the cathode of the diode 43 and the anode of the diode 51).
Commonly connected and connected to one end of the capacitor 45. The other end of the capacitor 45 is connected to the ground point 14.

Next, the cathodes of the diodes 59, 61, and 63, which are the end points of the first, second, and third diode arrays, are commonly connected and connected to one end of the capacitor 65, and at the same time output terminals.
Connected to 99. The other end of the capacitor 65 is connected to the ground point 14.

Next, the push-up capacitor branch group will be described. Is the first connection point of the first diode array,
One end of the capacitor 13 is connected to the connection point between the cathode of the diode 7 and the anode of the diode 19. The other end of the capacitor 13 is connected to a terminal 8 to which one end of the first phase high frequency power supply 1 is connected. Similarly, one end of the capacitor 15 is connected to the connection point between the cathode of the diode 9 and the anode of the diode 21, which is the first connection point of the second diode array. The other end of the capacitor 15 is connected to the terminal 10 to which one end of the second phase high frequency power source 3 is connected.
Further, one end of the capacitor 17 is connected to the connection point between the cathode of the diode 11 and the anode of the diode 23, which is the first connection point of the third diode array. This capacitor
The other end of 17 is connected to a terminal 12 to which one end of the third phase high frequency power source 5 is connected. These make up the first-stage push-up capacitor branch group.

Next, the second-stage push-up capacitor branch group is similarly constructed. One end of the capacitor 33 is connected to the third connection point of the first diode row, that is, the connection point between the cathode of the diode 27 and the anode of the diode 39. The other end of the capacitor 33 is connected to the terminal 8 to which one end of the first phase high frequency power supply 1 is connected. Similarly, one end of the capacitor 35 is connected to the third connection point of the second diode array, that is, the connection point between the cathode of the diode 24 and the anode of the diode 41. The other end of this capacitor 35 is a terminal 10 to which one end of the second phase high frequency power supply 3 is connected.
It is connected to the. In addition, the cathode of the diode 31 and the diode 43, which is the third connection point of the third diode row,
One end of the capacitor 37 is connected to the connection point with the anode of the. The other end of the capacitor 37 is connected to the terminal 12 to which one end of the third phase high frequency power source 5 is connected.

Next, the push-up capacitor branch group of the third stage is similarly constructed. One end of the capacitor 53 is connected to the connection point between the cathode of the diode 47 and the anode of the diode 59, which is the fifth connection point of the first diode array. The other end of the capacitor 53 is connected to a terminal 8 to which one end of the first phase high frequency power supply 1 is connected. Similarly, one end of the capacitor 55 is connected to the fifth connection point of the second diode array, which is the connection point between the cathode of the diode 49 and the anode of the diode 61. The other end of the capacitor 55 is a terminal 10 to which one end of the second phase high frequency power supply 3 is connected.
It is connected to the. In addition, the cathode of the diode 51 and the diode 63, which is the fifth connection point of the third diode array.
One end of the capacitor 57 is connected to the connection point with the anode of the. The other end of the capacitor 57 is connected to the terminal 12 to which one end of the high frequency power source 5 of the third phase is connected.

Next, the operation will be described. First, the first-phase high-frequency power supply 1 will be described. When the terminal 2 side of the high frequency power source 1 is positive, the diode 7 is turned on and the capacitor 13 is charged to the peak value e with the polarity shown. Next, high frequency power source 1
When the terminal 8 side of is positive, the diode 7 is off, and the sum of the charging voltage of the capacitor 13 and the high-frequency power source 1 charges the capacitor 25 via the diode 19 with the polarity shown. . The charging voltage of this capacitor 25 is 2e. Next, when the terminal 2 side is positive, the high frequency power source 1
The voltage 3e, which is the sum of the voltage of 2 and the voltage of the capacitor 25, turns on the diode 27 and charges the capacitor 33. The charging voltage of this capacitor 33 is 3e. When the charging voltage of the capacitor 13 is lower than e, a current that compensates for the decrease flows through the diode 7. Next, when the terminal 8 is also positive, the sum of the charging voltage of the capacitor 33 and the voltage of the high frequency power supply 1 flows through the diode 39 to charge the capacitor 45. The charging voltage of this capacitor 45 is 4e. Next, when the terminal 2 side is positive again, the voltage 5e which is the sum of the voltage of the high frequency power supply 1 and the voltage of the capacitor 45 turns on the diode 47 and charges the capacitor 53. The charging voltage of this capacitor 53 is 5e. Next, in the section where terminal 8 is positive again,
The sum of the charging voltage of the capacitor 53 and the voltage of the high frequency power supply 1 flows through the diode 59 and charges the capacitor 65. The charging voltage of this capacitor 65 is 6e.

Next, regarding the second-phase high-frequency power supply 3, in the above description, the diode array is changed from the first diode array to the second diode array, and the boosting capacitor groups are respectively replaced by the second high-frequency power supply 3. Smoothing capacitor group 25, 45, 65 by changing to the corresponding capacitor
Also, as in the case of the first-phase high frequency power supply 1, rectification charging is performed. The smoothing capacitor groups 25, 45, 65 are also charged in the same manner for the third-phase high-frequency power source 5. In this way, the smoothing capacitor groups 25, 45, 65 have the first phase, the second phase,
Charging is performed sequentially from the third-phase high-frequency power source in accordance with the phase.

The above-described embodiment can be modified as follows within the scope of the present invention. First, the high frequency power supply is not limited to three phases, but can be changed to any n phase.
In that case, the object can be achieved by replacing the number of branch groups of the boosting capacitors and the number of diode rows corresponding thereto with an arbitrary number. Also, the number of stages can naturally be increased or decreased to any number. Also the third
By changing the polarity of the diode in reverse, negative DC high voltage output can be generated. Fourthly, it is also possible to construct a bipolar high voltage generator by combining the negative polarity high DC voltage generator constructed as described above and the positive polarity high DC voltage generator. is there. Fifth, the output voltage is not limited to the final stage of the smoothing capacitor branch group, and an output voltage according to the number of stages can be taken out from any stage in the middle. Sixth, the reference potential point is not limited to zero volt, and a potential according to need can be used as the reference potential point. In addition, each capacitor is not limited to a capacitor that is a ready-made component, but can be configured by using a floating electrostatic capacitance or by using an electrostatic capacitance between the center conductor and the outer conductor of the high-voltage cable. As for the high frequency power source, a high frequency inverter using an FET is generally used, but other electronic devices are also possible. Also, a high frequency generator of a rotating machine can be used.

[0017]

The present invention has the features described above,
Energy is directly applied from the high-frequency power supply to the capacitor branch group, and is driven by the multiphase high-frequency power supply, which improves the voltage fluctuation rate and ripple characteristics of the rectifier. Therefore, the required capacitance of the capacitor can be reduced, which is advantageous when using the floating capacitance. Further, since the voltage doubler rectification operation is multiple and parallel, the boosting characteristic can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a DC high voltage generator according to the present invention.

FIG. 2 shows an example of a conventional DC high voltage generator.

[Explanation of symbols]

1, 3, 5 ... High frequency power source 2, 4, 6, 8, 10, 12 ... Terminals 7, 9, 11, 19, 21, 23, 27, 29, 31, 39, 41, 43, 4
7, 49, 51, 59, 61, 63 ... Diodes 13, 15, 17, 25, 30, 35, 37, 45, 53, 55, 57, 65 ... Capacitor 14 ... Ground point 99 ... Output terminal

Claims (1)

[Claims] 1. An n-phase high-frequency power source connecting terminal having a neutral point connected to a reference potential point; one end of each is connected to the reference potential point, and 2 m-stage diodes are connected in series in the same direction. n sets of diode strings; a branch group of push-up capacitors each having one end of m capacitor means connected to each high-frequency power supply connection terminal commonly connected; one end of each of which is connected to the reference potential point a smoothing capacitor group consisting of m capacitor means: connecting even-numbered connection points of each of the diode arrays in common and connecting to terminals of the smoothing capacitor branch group, respectively, diodes of each phase Each of the odd-numbered connection points of the columns is connected to a terminal of the boosting capacitor branch group of each phase, and a DC high voltage output is obtained from the terminals of the smoothing capacitor branch group. High-voltage generator.