Medical equipment refers to all equipment that uses X-ray, ultrasonic, magnetic field, nuclear and other energy to irradiate organs in the body, uses film or reviewer to receive its transmission image or reflection image, takes the image diagnosis of obtaining information as the first, and uses electricity to treat and inspect rays, light, heat, reagents, etc. With the rapid development of cutting-edge electronic technology, these devices have also made great progress in technology.
In the past and now, in terms of diagnosis, the X-ray department is the power supply on the mainstream X-ray equipment, and the x-high voltage device has considerable particularity from its occurrence principle. Because the X-ray tube (2 and 3-pole vacuum tube) generates X-rays by using the transformation of the motion energy of the heavy metal target in the tube under the electron beam collision and the orbital electron migration of the target, it needs the power supply of DC high voltage applied to the two poles of the X-ray tube to heat the cathode filament.
The requirements of x high voltage device for power adapter are:
(1) Due to the generation of very high voltage, advanced insulation technology, safety and reliability are required.
(2) The instantaneous power required is large and has the ability to provide this power.
(3) In order to obtain appropriate X-ray exposure, tube voltage, tube current and irradiation time can be controlled arbitrarily.
(4) The switching frequency is high, so it is required to have excellent stability, linearity, repeatability and repeated operation life.
From a technical point of view, its application scope takes power electronics (using relatively large transformers or power components) as the main body, including microcomputer, various semiconductors, motor auxiliary control circuit and many departments involved. Therefore, it can be said that it brings together all the technologies of industrial electronics. In addition to safety, high reliability and high performance. Like the general power supply, it requires low price, small volume, high efficiency, and the organic combination of power adapter and hardware.
The power supply of X-ray high-voltage device is classified according to the high-voltage generation principle, which can be roughly divided into transformer type and capacitor type. The characteristics of various modes should be flexibly applied. According to the highest voltage, it can be divided into three categories: 120kv, 125kV and 150kV. It can also be distinguished according to the maximum rated current or according to the capacitance of the capacitor in the capacitor type device.
Single phase full wave rectifier transformer type high voltage device. This is one of the most popular high-voltage devices. Input a 50Hz or 60Hz sine wave from a single-phase AC power supply, boost it to a high voltage of 20 ~ 150kV with a high-voltage transformer, and then rectify the rectifier trap bridged by four high-voltage rectifiers and send it to the X-ray tube. Therefore, the tube voltage waveform is the single-phase full wave rectification waveform and the basic unit of irradiation time; A half cycle peak is called a pulse, and the irradiation time is an integral multiple of this pulse. That is, when the power supply is 50Hz, 10 milliseconds is the control unit.
Three phase full wave rectifier transformer type high voltage device. Because the three-phase input power supply is easy to provide high power, it is adopted by high power output. The waveform pulsation rate of the tube voltage of the AC uninterruptible power supply device is less, and the X-ray exposure per unit time is more than the above single-phase full wave rectification mode, so it has begun to be popularized rapidly recently. There are two kinds of high voltage generation circuits of three-phase full wave rectification: 6-peak mode and L2 peak mode.
(1) 6 peak mode. The secondary side of the high-voltage transformer is connected into a Ya shape, which is composed of six rectifiers. The Ya shaped wiring of two groups of secondary is connected in series to form a double 6-peak rectification mode.(2) 12 peak rectifier. Connect the secondary coils of the high-voltage transformer into A-shaped wiring and A-shaped wiring. If they are connected in series, the phase difference of each coil of the secondary is 30 °, and its rectified output is 12 peaks.
Capacitor type high voltage device. Different from the above transformer mode, because the capacitor is used for energy storage and release, it can only be used as a small capacity power supply without tube voltage pulsation. It is suitable for short-time irradiation. If continuous irradiation, the tube voltage decreases, so it can not be used for continuous irradiation. On the high voltage side, a capacitor with large capacitance is connected in parallel with the X-ray triode. When the charging reaches the specified tube voltage, X-ray irradiation is carried out by controlling the grid bias of the X-ray triode. The charging circuit adopts voltage doubling rectifier circuit.
Choosing Guangshu power supply has chosen energy conservation, safety, environmental protection and long service life. Guangshu currently produces security power supply, small household appliance charger, USB charger, balance car charger, lithium battery charger, musical instrument power supply, digital power supply and communication power supply.
