JPH0720575U - DC high voltage measuring instrument - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the voltage detection speed. [Structure] The generator voltmeter 3 has a fixed electrode plate 4 and a rotating electrode plate 5, and is arranged so as to face the high voltage application object 2 to be measured. The output voltage Vg of the generator voltmeter pulsating in a triangular wave or a sine wave is introduced into the peak value detection circuit 14 via the buffer amplifier 9. The detection circuit has a reset signal S
_It is periodically reset by ₂ and the peak value of the output voltage Vg is detected in each detection cycle. The sample / hold circuit 17 responds to the sample command signal S ₁ to sample the peak value signal Vp of the peak value detection circuit, hold the sampled value, and detect the detected voltage proportional to the peak value of the output voltage Vg of the generator voltmeter. Output Vo.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a DC high voltage measuring instrument using a capacitive coupling type generator voltmeter, and relates to a measuring instrument having an improved voltage detection speed.

[0002]

[Prior art]

 A generator voltmeter (GVM: generating volt-meter) is used to measure the acceleration voltage in the tandem accelerator, and the DC high voltage can be measured with good accuracy and linearity. Figure 3 shows the DC high voltage measuring system in which the high voltage terminal voltage of the tandem accelerator to which the DC high voltage is applied is measured by the generator voltmeter and the measured output is used to control the DC high voltage power supply. It is a block diagram. The high voltage Vd to be measured is applied from the high voltage DC power supply 1 to the high voltage terminal 2 of the tandem accelerator. The tandem accelerator is housed in a pressure tank filled with high-pressure insulating gas, and a generator voltmeter 3 is mounted on the wall of the pressure tank so as to face the high-voltage terminal 2.

The generator voltmeter 3 has a fixed electrode plate 4 and a rotating electrode plate 5, and the rotating electrode plate is driven by a motor 6. As shown in FIG. 4, each of the fixed electrode plate 4 and the rotating electrode plate 5 has a plurality of, for example, seven fan-shaped portions 4 ₁ and 5 ₁ . The fixed electrode plate 4 is connected to a capacitor 7 whose one end is grounded, and the rotating electrode plate 5 is grounded. Fan-shaped portion 4 ₁ of the fixed electrode plate 4 is a high voltage capacitor - charging current to the fixed electrode plate by capacitive coupling when facing the Terminal 2 flows, the shield fan-shaped portion 4 ₁ is the fan-shaped portion 5 ₁ of the rotating electrode plate 5 Discharge current flows from the fixed electrode plate to the rotating electrode plate. Along with this, the output voltage Vg of the generator voltmeter 3 generated at the terminal of the capacitor 7 pulsates in a triangular wave or sine wave shape as shown in FIG. The output voltage Vg is divided by the resistance voltage divider 8 and introduced into a buffer amplifier 9 such as a voltage follower, and the output of the amplifier is applied to the RC filter circuit of the resistor 10 and the capacitor 11 to the terminal of the capacitor 11. The output voltage Vg is smoothed, and the detection voltage Vo having a small ripple proportional to the high voltage Vd applied to the high voltage terminal 2 is obtained. This detection voltage Vo is taken out via the buffer amplifier 12 and given to the power supply control circuit 13 of the high voltage power supply 1 to adjust the output voltage of the high voltage power supply to a predetermined value.

[0004]

[Problems to be solved by the device]

The triangular or sinusoidal pulsating frequency of the output voltage Vg of the generator voltmeter 3 obtained from the capacitor 7 is usually about 400 Hz (the motor 6 rotates 60 times per second, the fixed electrode plate 4 and the fan-shaped portion 4 of the rotating electrode plate 5). _If the number of ₁ , 5 ₁ is 7, it will be 420 Hz.). Therefore, in order to obtain the detection voltage Vo with an accuracy (ripple) of 0.1%, the time constant (RC) of the RC filter circuit including the resistor 10 and the capacitor 11 must be set to about 2 sec or more. The voltage controlled response of unity cannot be faster than this.

An object of the present invention is to provide a direct current high voltage measuring device which improves the speed of voltage detection based on the generator voltmeter 3.

[0006]

[Means for Solving the Problems]

 The present invention is a generator-voltage meter equipped with a fixed electrode plate facing a high voltage applying body to be measured, and a rotating electrode plate disposed between the applying body and the fixed electrode plate and periodically shielding the fixed electrode plate. The DC high-voltage measuring instrument according to the standard is equipped with a peak value detection circuit that detects the peak value of the output of the generator voltmeter and is reset periodically, and a sample and hold circuit that responds to the output of this peak value detection circuit. It is characterized by

[0007]

[Action]

 The peak value of the output voltage of the generator voltmeter is periodically detected and the detected peak value is sampled and held to detect the value of the measured high voltage. It is not affected by the pulsation of the output voltage of the generator voltmeter, does not need to be smoothed, and the voltage detection speed is determined by the detection period.

[0008]

Embodiment An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of the embodiment, FIG. 2 is a waveform explanatory diagram of each part, and the same reference numerals as those in FIGS. 3 and 5 indicate the same parts. The generator voltmeter 3 is provided so as to face the object to which the high DC voltage Vd to be measured is applied, for example, the high voltage terminal 2 of the tandem accelerator, and is provided at the connection point between the fixed electrode plate 4 and the capacitor 7. The output voltage Vg of the generator voltmeter 3 is generated. A voltage obtained by dividing the output voltage Vg pulsating in a triangular wave shape or a sine wave shape by the resistance voltage divider 8 is introduced into the peak value detection circuit 14 via the buffer amplifier 9.

The peak value detection circuit 14 for detecting the peak value Vp of the output of the buffer amplifier 9 periodically uses the reset signal S _{2 obtained} by delaying the clock signal S ₁ of the clock generation circuit 15 by the delay circuit 16 by the time td. It is reset and detects the peak value of the output voltage Vg of the generator voltmeter 3 for each detection cycle and outputs the peak value signal Vp. The peak value signal Vp is held by the sample and hold circuit 17. The sample-hold circuit uses the clock signal S ₁ of the clock generation circuit 15 as a sample command signal, samples the peak value signal Vp immediately before resetting of the peak value detection circuit 14, and holds the sampled value to generate power. The detection voltage Vo that is proportional to the peak value of the output voltage Vg of the voltmeter 3 is output. The cycle of the clock signal S ₁ of the clock generation circuit 15, that is, the peak value detection and the sample and hold cycle is selected to be about 10 msec in consideration of the pulsating cycle of the output voltage Va of the generator voltmeter 3.

[0010]

[Effect of device]

 As described above, the present invention detects the peak value of the output voltage of the generator voltmeter, and samples and holds this to detect the DC high voltage value. It is not necessary to smooth the pulsation of the output voltage of the meter, and the detection speed depends on the peak value detection cycle, and the detection speed can be significantly improved without lowering the measurement accuracy.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a waveform explanatory diagram of each part in the example.

FIG. 3 is a configuration diagram of a conventional example.

FIG. 4 is a configuration diagram of an electrode plate in the generator voltmeter.

FIG. 5 is a waveform explanatory diagram of each part in the conventional example.

[Explanation of symbols]

 2 Object to be measured high voltage application (high voltage terminal) 3 Generator voltmeter 4 Fixed electrode plate 5 Rotating electrode plate 14 Peak value detection circuit 17 Sample and hold circuit

Claims (1)

[Scope of utility model registration request] 1. A generator voltmeter comprising a fixed electrode plate facing an object to which a high voltage to be measured is applied, and a rotating electrode plate arranged between the applying member and the fixed electrode plate to periodically shield the fixed electrode plate. In the DC high voltage measuring instrument by, the peak value detection circuit that detects the peak value of the output of the generator voltmeter and is reset periodically, and the sample and hold circuit that responds to the output of this peak value detection circuit are provided. A DC high voltage measuring instrument characterized by: