JPH02156163A - Output voltage detector of high voltage rectifier - Google Patents

Abstract

PURPOSE:To make it possible to exclude unbalance in reverse voltage accompanied by neither a complicated constitution nor the increase in loss by a constitution wherein the role of a balance resistor is shared by voltage dividing resistors. CONSTITUTION:In a high voltage rectifier circuit, unit rectifiers 1A-1C which are wired in a bridge form are wired in cascade pattern by a plurality of stages. A step-up transformer 2 has secondary windings 2A-2C which are connected to the rectifiers 1A-1C, respectively. A resistive potential divider 14 comprises several stages of unit resistive potential dividers 14A-14C which have phase compensating capacitors C1-C3 that are connected to the rectifiers 1A-1C in parallel and have the equal resistance value. A voltage detecting resistor 14d having a voltage dividing resistor Rd and a capacitor Cd is connected to a voltage dividing resistor R1 and a capacitor C1 of the potential divider 14A. The detected voltage is converted into the output voltage in an output voltage detector 6 and the result is outputted. Thus, the resistive potential dividers 14A-14C serve the function of a balance resistor, and the constitution of the detector is simplified. The unbalanced distribution of reverse voltages is excluded, and the rectifier element can be protected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a voltage detection device including a resistive voltage divider for measuring an output high voltage of a DC high voltage generator or the like.

[Conventional technology]

Figure 2 is a connection diagram showing a conventional device, high voltage rectifier circuit 1
are unit rectifiers iA, IB in which different numbers of rectifying elements 10 are connected in series as required.

10 etc. are connected in cascade in a plurality of round shapes, one end of the unit rectifier 1A at the bottom stage is grounded, and the high voltage end of the unit rectifier 1C at the top stage is conductively connected to the load 5. 2 is a step-up transformer, whose secondary windings 2A, 2B, 2
0 corresponds to the number of cascades of unit rectifiers, and in the case of the figure, it is divided into 6 parts, each connected to a unit rectifier, and the primary winding of the transformer is connected to an AC power supply part 6 having a voltage control bag fit, so that each unit long current is connected to the unit rectifier. By applying mutually equal AC voltages to the devices IA, IB, and 1C, the output DC voltage V is applied to the load 5.
is applied. Further, the output voltage V is detected by a resistive voltage divider 4 having a phase compensation capacitor connected in parallel to the output side of the high voltage rectifier circuit 1, and the output voltage V is determined by an output voltage detection section 6.

Note that in the resistor voltage divider 4, the detection resistor R1 is the voltage dividing resistor R
,,R, and the time constant R1・C,
, R, ・C, , R3 ・C8 are equal to each other, then the voltage division ratio of the resistive voltage divider 4 is K = Rt 1Rz 1Rs
/R+, so if the detected voltage is Vd, the output voltage V becomes v=x-vd, and the output voltage is calculated and outputted by the output voltage detection section 6.

[Problem to be solved by the invention]

In the conventional device, when the power supply 3 of the high-voltage rectifier circuit 1 that generates the output DC voltage v1 is cut off, the capacitance of the load 5 and the phase compensation capacitor (hereinafter abbreviated as capacitor) C
IIC! A reverse voltage is applied to the long current element 10 of the high voltage rectifier circuit 1 due to the electric charge accumulated in the floating capacitor 103 and the stray capacitance. If the reverse leakage characteristics of the rectifier elements 10 are the same, the reverse voltage will be divided equally to each element, but in reality, the characteristics may vary and an excessive reverse voltage may be applied to some elements. The problem arises that

In order to prevent dielectric breakdown of the element due to uneven distribution of reverse voltage, there is a method of providing a margin for the reverse withstand voltage of the rectifying element 10;
A method is known in which balance resistors 7A, 7B, 7C, etc. are connected in parallel to each of the unit GL currents IA, IB, and 1C to equalize the reverse voltage distribution for each 2i unit current flow device.

However, in the former case, there are problems with the increase in the number of series elements, resulting in uneconomical effects and an increase in the size of the device.In the latter case, when a high voltage is generated, part of the output current flows through the balance resistor, resulting in an increase in loss. The exhaust heat treatment becomes a problem, and the configuration of the device becomes complicated.

An object of the present invention is to eliminate reverse voltage imbalance without complicating the configuration or increasing loss by providing a voltage dividing resistor with the role of a balance resistor.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a high voltage rectifier circuit in which a plurality of bridge-connected unit rectifiers are connected in cascade, and
In a high-voltage current transistor having a step-up transformer having J number of secondary windings, the bottom stage is composed of multiple stages of unit resistor voltage dividers of equal resistance value each having a phase autopsy capacitor connected in parallel to the unit rectifier. a resistive voltage divider having all current sensing resistors connected in series to the ground side of the unit resistive voltage divider;
a 'ltl galvanic resistor connected in series to the ground side of the high-voltage rectifier circuit to detect the output current of the high-voltage rectifier circuit, and outputting the lower voltage of the secondary winding corresponding to the detected current of 7; It is assumed that the circuit includes a voltage 4-lower calculation section, and a corrected output voltage calculation section disposed on the output side thereof, which corrects the voltage drop and then outputs the entire detected voltage of the resistor voltage divider.

[Effect]

In the above means, phase compensation capacitor? It consists of unit resistor voltage dividers with equal resistors corresponding to the number of cascade stages of all unit rectifiers, and the unit resistor voltage divider 6 of each stage is connected to the unit current converter in parallel with the unit rectifier, and the unit of the first stage is By configuring the resistor voltage divider to use a detection resistor gold film to determine the output voltage "Jf" in the output voltage detection section, the unit voltage divider resistor also functions as a balance resistor, simplifying the configuration of the device. It is possible to protect the rectifying element by eliminating uneven distribution of reverse voltage.

Ninth, by connecting the unit resistance voltage divider in parallel to the unit GL current transformer in each stage, there is a difference in impedance voltage drop in the secondary winding of the step-up transformer connected to each unit rectifier, and the difference in impedance voltage drop of each unit rectifier If an imbalance occurs in the output '1 voltage, the shared voltage of each unit resistor voltage divider will also become uneven, but if the total output voltage V is calculated by multiplying the detected voltage VdK of the voltage detection resistor by the voltage division ratio K, the above shared voltage will be It is impossible to detect voltage imbalance, and a new problem arises in that the output voltage detection section outputs a value higher than the actual output voltage. In this invention, focusing on the fact that the impedance voltage drop changes in proportion to the output current, a current detection resistor is provided on the ground side of the high voltage rectifier circuit to detect the output current, and the detected current is The voltage drop of each unit rectifier is calculated based on the voltage drop of each unit rectifier, and the correction output calculation section corrects the detected voltage of the output voltage detection section, thereby eliminating the negative effects caused by the resistance voltage divider doubling as a balance resistor. Ru.

〔Example〕

The following description will be made based on all the embodiments of this invention.

FIG. 1 is a connection diagram showing a device according to an embodiment of the present invention, and the same reference numerals are used for the same parts as in the conventional device, and detailed explanation will be omitted. In the figure, 14 is a resistive voltage divider, and unit resistive voltage dividers 1 are connected in cascade to each other.
It consists of 4A, 14B, and 14C, and each unit resistor voltage divider is a unit rectifier 1A.

A voltage detecting resistor 14d having a capacitor Cd in series with a voltage dividing resistor R1 and a phase compensation capacitor C1 is connected to the unit resistor voltage divider 14A at the lowest stage, which is connected in parallel to the voltage dividing resistor R1 and the phase compensation capacitor C1. is converted into an output voltage V by the output voltage detection section 6 and output. That is, the resistance values R1+Rd, R, and R3 are equal to each other, and Rcj/, (R1, and each unit resistor voltage divider 14A, 14B).

Under the condition that the time constants of 14C2 and 14d are equal to each other, the voltage division ratio of the resistive voltage divider 14 is = (R1 + R2 + R,
+Rd)/Rd, r, v=x, Vd Kj, the output voltage ■ can be obtained.

By the way, the secondary windings of the step-up transformer 2 have different DC to ground voltages, and require higher withstand voltage strength in the order of 2A, 2B, and 2C, so they are usually arranged inside the winding i2A'. Windings 2B, 2Ct - successively outer concentric windings are used. In such a case, the winding resistance and leakage reactance are larger as the windings are arranged on the outer side, and therefore the impedance voltage drop proportional to the output current also becomes larger. As a result, the output voltages VA, VB of each unit Ii current flow controller
, VC also shows a slope that becomes lower towards the top. Therefore, in the embodiment device, a current detection resistor 1 is connected to the ground side of the high voltage rectifier circuit 1.
5 is provided to detect the output current voltage 1, and the voltage drop calculation section 16
The impedance voltage drop is determined by the correction output calculation section 17.
By correcting the detected voltage of the output voltage detection part B,
It is configured to accurately measure the actual output voltage V2.

In the example device, the rated output current was set to 0. Assuming that the open voltage of the secondary winding I gland is f Vo , the output voltage fV'a , Vb , Vc of the secondary winding in the electrician 1, and the impedance voltage drop is %Za, %Zb1%Zc, each winding in the electrician 1 The output voltages Va, Vb, and Vc are expressed by the following equations.

Va=Vo-41-%Za/100-I.

Vb=Vo-Ii-%Zb/IQQ・I.

Vc=Vo-Ii (%Za+%zb+%
Zc)/100・Work 0 Also, since %Za(%zb<%ZC, Va+Vb+Vo becomes smaller than 3Va, and the DC output voltage V also decreases in proportion to this.Resistance voltage divider 1
The measurement principle of No. 4 is to obtain the output voltage on the assumption that it is proportional to 3 Va, and cannot detect the impedance voltage drop.

Therefore, in the embodiment device, 2B, '2C with respect to the leakage impedance %Za of the secondary winding 2A of the step-up transformer 2.
Sum of increments of leakage impedance %Zb1%Zc %ΔZ
Calculate the actual value of the transformer in advance using the following formula.

%ΔZ=%zb10%Zc-2%Za ・・・・・・
...(1) Next, the first current detection resistor 15 outputs '
1! The leakage impedance 1 is detected, and the voltage drop calculation unit 16 calculates the voltage drop % using the output current flow 1 and the leakage impedance %ΔZi.
Calculated using the Δv linear equation.

%Δv=-work 1・%ΔZ/100・work 0・・・・・・
(2) Therefore, in the corrected output calculation unit 17, by adding the negative voltage drop %ΔV obtained in the correction voltage calculation unit 16 to the output voltage V detected by the output voltage detection unit 6, The corrected output voltage can be obtained using the following equation.

v 10% Δv = v + (-1-% ΔZ/ID0-IO)・
...(3) Note that the voltage drop in each of the above equations indicates the voltage drop in the secondary winding of the transformer, and must be converted into a DC voltage by both calculation units 16 and 1i17. Needless to say, the method of calculation is not limited to the above formulas.

〔Effect of the invention〕

As described above, in this invention, a resistor voltage divider is constructed of a plurality of cascade-connected unit resistor voltage dividers and is connected to a unit rectifier that is also cascade-connected. A current detection resistor and a voltage drop calculation unit are provided to calculate the voltage drop corresponding to the load current, and the corrected output calculation unit compares the voltage with the measured voltage of the resistor voltage divider to calculate the corrected output voltage. did.

As a result, the resistance voltage divider also serves as the balance resistor in the conventional device, so it is not necessary to provide a balance resistor.
This eliminates the increase in loss caused by the electric current and the uneven distribution of the reverse voltage applied to the rectifier due to residual charge, which prevents a decrease in efficiency and damage to the rectifier, and also reduces the number of rectifiers in series, simplifying the configuration. A rectifier can be provided. Furthermore, the measurement error of the voltage dividing resistor caused by the difference in the impedance voltage drop of the secondary winding of the transformer connected to each unit rectifier is caused by the current detection resistor and the current detection resistor that corrects the voltage drop corresponding to the load current The provision of two calculation units eliminates the negative effects of using a voltage dividing resistor as a balance resistor, making it possible to use a high voltage rectifier equipped with a multifunctional and highly accurate output voltage detection device. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing an embodiment of the present invention, and FIG. 2 is a connection diagram showing a conventional device. 1... High voltage rectifier circuit, 1A, 1B, IC... Unit rectifier, 2... Step-up transformer, 2A, 2B, 2C"°° secondary winding, 6... m source, 4, 14...resistance voltage divider,
14A, 14B, 14C...unit resistance voltage divider, 14d
... Voltage detection resistor, 5... Load, 6... Output voltage detection section, 10... Rectifying element, 15... Current detection resistor, 16... Voltage drop calculation section, 17 ...Corrected output voltage calculation section, R...Resistor, C...Capacitor, ■
...output voltage, ΔV...voltage drop, min.1...output current. /Ya [Seiryo Kaigojo Z Gen] Otsu Figure 1

Claims (1)

[Claims] 1) In a high-voltage rectifier including a high-voltage rectifier circuit in which bridge-connected unit rectifiers are cascaded in multiple stages, and a step-up transformer having a plurality of secondary windings connected to each of the unit rectifiers, in parallel with the unit rectifier. A resistive voltage divider consisting of multiple stages of unit resistive voltage dividers with mutually equal resistance values and having phase compensation capacitors connected thereto, a resistive voltage divider having a voltage detection resistor connected in series to the ground side of the lowest stage unit resistive voltage divider, and the high voltage a current detection resistor connected in series to the ground side of the rectifier circuit to detect the output current of the high-voltage rectifier circuit; and a voltage drop calculation unit to calculate the voltage drop of the secondary winding corresponding to the detected current. An output voltage detection device for a high voltage rectifier, comprising: a corrected output voltage calculation unit that outputs a detected voltage of the resistive voltage divider whose voltage drop has been corrected.