JPH0745048U - High frequency x-ray generator - Google Patents

Abstract

(57) [Abstract] [Purpose] To enable transition to different intermediate circuit voltages that may be located above and below the current actual value without overshoot. [Structure] The adjustment circuit of the intermediate circuit voltage, as an adjustment element,
The firing angle α is determined by the function generator 14 controlled by the conditioner 11 for the intermediate circuit voltage UZ, compensating for the non-linear relationship between the firing angle α and the output voltage UN of the rectifier 1. It has a controllable rectifier 1.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention comprises a DC voltage intermediate circuit provided between a power supply connection and an inverter for supplying a high voltage transformer to generate an X-ray tube voltage, and an intermediate circuit voltage adjusting circuit. High frequency X-ray generator.

[0002]

[Prior art]

 In recent X-ray technology, high frequency X-ray generators are mainly used. The DC voltage intermediate circuit then supplies the input voltage of the inverter. This input voltage, ie the intermediate circuit voltage, must be adjusted to different values in order to obtain the optimum conditions.

[0003]

[Problems to be solved by the device]

 The object of the present invention is to ensure that a transition to different intermediate circuit voltages which can lie above and below the actual value of the real world is ensured without overshoot, so that a high-frequency X-ray generator of the kind mentioned at the outset is ensured. Is to configure.

[0004]

[Means for Solving the Problems]

 According to the invention, the regulation circuit for the intermediate circuit voltage, according to the present invention, comprises, as a regulating element, a state regulator for the intermediate circuit voltage by compensating for the non-linear relation between the firing angle and the output signal of the rectifier. It is solved by having a controllable rectifier whose firing angle is determined by a function generator controlled by.

[0005]

[Operation effect]

 Generally, the transfer characteristic of a controllable rectifier formed as a thyristor bridge depends on the firing angle of the output voltage and the power supply voltage. The non-linear relationship between the firing angle and the output voltage is compensated depending on the firing angle by connecting in series an inverse characteristic circuit for the output voltage. The peak value of the power supply voltage is detected by a suitable measuring circuit, and the inverse characteristic is standardized using this value. This makes the transfer characteristic linear and independent of the power supply voltage. This allows the use of the conditioner.

[0006]

【Example】

 Next, the present invention will be described in detail with reference to the embodiments shown in the drawings.

The high frequency X-ray generator shown in FIG. 1 has a controllable rectifier 1 connected to a power supply, after which a filter circuit 2 is connected. This filter circuit 2 supplies an intermediate circuit voltage UZ which forms the input voltage of the inverter 3. The inverter 3 feeds the high voltage transformer 4. An X-ray tube 5 is connected to the secondary winding of the high voltage transformer 4 via a high voltage rectifier 6. A regulating circuit 7 is provided for regulating the intermediate circuit voltage UZ.

FIG. 2 shows the configuration of the rectifier 1 composed of a controllable thyristor in detail. UN is attached to the output voltage. Further, as shown in FIG. 2, the filter circuit 2 includes an LC circuit 8 having a resistance R I and an inductance L, and an RC circuit 9 having a capacitor C and a resistance RL. The output voltage of the filter circuit 2 is the intermediate circuit voltage UZ. In FIG. 2, IG is attached to the output current of the rectifier 1, and ILast is attached to the load current.

FIG. 3 shows the configuration of the adjusting circuit 7 in detail. Block 10 is the controlled object, block 11 is the conditioner for the intermediate circuit voltage UZ, and block 12 is the characteristic inverter of the rectifier 1 for matching with the supply voltage.

The functions of the components present here in the controlled object are indicated by corresponding blocks and adders. A signal UZSoll corresponding to the target value of the intermediate circuit voltage is applied to the input terminal 13 of the state controller 11. Its function is likewise represented by blocks, the values K0, K1 and B0 being constants. The characteristic inversion is performed by the function generator 14 which determines the firing angle α according to a predetermined formula. It should be noted that a 1, b and c are input signals of the characteristic inverter 12 and can be obtained as shown. US is the peak value of the power supply voltage, and K2 is another constant.

The characteristic inverter can be realized by a compound A / D converter, an EPROM having an inverse characteristic, and a compound D / A converter. It can be standardized by reference input of multiple components.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of a high frequency X-ray generator according to the present invention.

FIG. 2 is a circuit diagram showing in detail a part of the high frequency X-ray generator shown in FIG.

3 is a circuit diagram showing in detail another part of the high frequency X-ray generator shown in FIG. 1. FIG.

[Explanation of symbols]

 1 Rectifier 2 Filter circuit 3 Inverter 4 High voltage transformer 5 X-ray tube 6 High voltage rectifier 7 Regulator circuit 8 LC circuit 9 RC circuit 10, 11 block 12 Characteristic inverter 13 Input terminal 14 Function generator

Claims (2)

[Scope of utility model registration request] 1. A DC voltage intermediate circuit (2) provided between a power supply connection and an inverter (3) for supplying a high voltage transformer (4) to generate an X-ray tube voltage,
An adjusting circuit (1, 2, 7) for the intermediate circuit voltage (UZ), which adjusting element is between the firing angle (α) and the output signal (UN) of the rectifier (1). Conditioner (1) for the intermediate circuit voltage (UZ) by compensating the non-linear relation
1) A high-frequency X-ray generator having a controllable rectifier (1) whose firing angle (α) is determined by a function generator (14) controlled by 1). 2. A high-frequency X-ray generator according to claim 1, characterized in that the function generator (14) is supplied with a peak value (US) of the system voltage in addition to the output signal (a) of the condition controller. .