JPH11233286A5

JPH11233286A5 -

Info

Publication number: JPH11233286A5
Application number: JP1998044277A
Authority: JP
Filing date: 1998-02-12
Publication date: 2005-08-18
Anticipated expiration: 2018-02-12

Description

【００１７】
【課題を解決するための手段】
上記目的は、交流電源を受電しこれを整流するコンバータ回路と、このコンバータ回路の出力電圧を高周波の交流に交換するインバータ回路と，このインバータ回路の出力電圧を昇圧する高電圧変圧器と，この高電圧変圧器の出力電圧を整流する高電圧整流回路と，この高電圧整流回路の出力電圧である直流電圧を印加してＸ線を放射するＸ線管とを備えたインバータ式Ｘ線高電圧装置において、上記コンバータ回路は、上記交流電源の電圧と電流の位相を一致させると共に上記インバータ回路への入力電圧を所定の設定値と等しくなるよにすることによって達成される。
特に、上記コンバータ回路は、自己消弧可能なスイッチング素子とこのスイッチング素子と逆並列に接続されたダイオードから成る二組のスイッチングモジュールを直列に接続したスイッチングモジュール直列接続体と、このスイッチングモジュール直列接続体と並列に二つのコンデンサを直列に接続したコンデンサ直列接続体とで構成され、前記スイッチングモジュール直列接続体の接続点に交流リアクトルの一端を接続し、この交流リアクトルの他の一端と前記コンデンサ直列接続体の接続点に上記交流電源を接続し、この交流電源の電圧と位相差及び前記コンデンサ直列接続体の両端の電圧の設定値との誤差に応じて上記二組のスイッチングモジュールをパルス幅変調制御して前記交流電源の電圧と電流の位相を一致させると共に前記コンデンサ直列接続体の両端の電圧を設定値に制御するパルス幅変調制御回路を具備し、前記コンデンサ直列接続体の両端の電圧を上記インバータ回路に入力することによって達成される。[0017]
[Means for solving the problem]
The above object is achieved in an inverter type X-ray high voltage device comprising a converter circuit that receives and rectifies an AC power supply, an inverter circuit that converts the output voltage of the converter circuit into high-frequency AC, a high-voltage transformer that steps up the output voltage of the inverter circuit, a high-voltage rectifier circuit that rectifies the output voltage of the high-voltage transformer, and an X-ray tube that radiates X-rays by applying a DC voltage that is the output voltage of the high-voltage rectifier circuit, in which the converter circuit matches the phases of the voltage and current of the AC power supply and makes the input voltage to the inverter circuit equal to a predetermined set value.
In particular, the converter circuit is composed of a series-connected switching module assembly in which two sets of switching modules are connected in series, each set of switching modules being made up of a self-extinguishing switching element and a diode connected in anti-parallel to the switching element, and a series-connected capacitor assembly in which two capacitors are connected in series in parallel with the series-connected switching module assembly, one end of an AC reactor is connected to the junction of the series-connected switching modules, and the AC power source is connected to the junction of the other end of the AC reactor and the series-connected capacitor assembly, and a pulse-width modulation control circuit is provided which pulse-width modulates the two sets of switching modules in accordance with the phase difference between the voltage of the AC power source and the error between the voltage across the series-connected capacitors and a set value, thereby matching the phases of the voltage and current of the AC power source and controlling the voltage across the series-connected capacitors to a set value, and the voltage across the series-connected capacitors is input to the inverter circuit.

Claims

An inverter type X-ray high voltage device includes a converter circuit that receives AC power and rectifies it, an inverter circuit that converts the output voltage of this converter circuit into high frequency AC, a high voltage transformer that boosts the output voltage of this inverter circuit, a high voltage rectifier circuit that rectifies the output voltage of this high voltage transformer, and an X-ray tube that radiates X-rays by applying a high DC voltage that is the output voltage of this high voltage rectifier circuit,
The inverter type X-ray high voltage device is characterized in that the converter circuit matches the phases of the voltage and current of the AC power supply and makes the input voltage to the inverter circuit equal to a predetermined set value.

2. The inverter type X-ray high voltage apparatus according to claim 1, wherein the converter circuit comprises a series-connected switching module body in which two sets of switching modules, each of which is formed by connecting in series a self-extinguishing switching element and a diode connected in anti-parallel to the switching element, and a series-connected capacitor body in which two capacitors are connected in series in parallel with the series-connected switching module body, one end of an AC reactor is connected to a junction of the series-connected switching modules, and the AC power supply is connected to the junction of the other end of the AC reactor and the series-connected capacitor body, and further comprises a pulse-width modulation control circuit that performs pulse-width modulation control of the two sets of switching modules in accordance with a phase difference between the voltage and current of the AC power supply and an error between the voltage across the series-connected capacitor and a set value, to match the phases of the voltage and current of the AC power supply and to control the voltage across the series-connected capacitor to a set value , and

The inverter-type X-ray high voltage device according to claim 2, characterized in that the inverter circuit is formed by connecting two sets of the series-connected switching modules in parallel or by connecting one set of the series-connected switching modules in parallel, and these two sets of the series-connected switching modules or one set of the series-connected switching modules in parallel with the series-connected switching module of the converter circuit to form a three-phase switching module or a single-phase switching module, which is used in the converter circuit and the inverter circuit.