Design and development of the hottest pulse laser

2022-08-20
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Design and development of pulse laser power supply

1 introduction

although the traditional pulse laser power supply has achieved nonlinearity and replaced the old linear voltage doubling rectification technology, the overall conversion efficiency, volume, weight, charge and discharge time and other important parameters have been greatly improved. In addition, the continuous improvement and commercialization of the reliability of nonlinear laser power supply has made the application of laser technology to a new level. However, this nonlinear laser power supply still has the disadvantage that the working frequency is always below 20kHz and cannot be further improved. In this way, the conversion efficiency, volume, weight and charge and discharge time of the traditional nonlinear laser power supply cannot be improved to the ideal state. At the same time, there is very annoying audio noise. In order to solve these problems, we have successfully designed and developed a nonlinear pulse laser power supply with a working frequency of 100kHz

2 circuit composition

the principle block diagram of pulse laser power supply is shown in Figure 1. It consists of trigger circuit, main converter circuit and high-voltage charging and discharging circuit. Its circuit schematic diagram is shown in Figure 2

Figure 1 schematic block diagram of pulse laser power supply

Figure 2 schematic circuit diagram of pulse laser power supply

3 working principle of circuit

3.1 working principle of trigger circuit

it can be seen from Figure 2 that the trigger circuit is mainly composed of trigger indication circuit and trigger circuit, which is specifically completed by LBI and LBO terminals of IC1, V1, led, VD1, K1 and K2. By establishing enterprise library and law enforcement personnel library, the converter passes through transformer T1 When the diodes VD2 and VD3 charge the capacitor, the sampling circuit (composed of R10, R9, W1, W2, W3, R1) feeds back its charging voltage value to the LBI and VFB terminals of IC1. Once the voltage is charged to the required voltage value (about 1KV), the voltage value at the LBI terminal will be greater than 1.3V, and the LBO terminal will become high level, V1 will turn on, and the LED will turn on, indicating that the voltage has been charged to a state that can be triggered. In addition, the sampling circuit also sends the feedback signal to the VFB end of IC1. If the voltage value of the feedback signal is ≥ 1.3V, immediately turn off the converter to maintain the high voltage to the required value, and the trigger device is the automotive grade thyristor bt151/800r with high voltage withstand and high current

3.2 working principle of the main converter

the main converter circuit is mainly a single ended flyback boost circuit composed of IC1 (max641/642/643), transformer T1, V2 and other components. The core part of the circuit is max641/64. As a whole, it is 2/643. Therefore, please refer to the literature for the working principle analysis of this part of the circuit and the technical parameters and applications of max641/642/643. Here, only the technical data of high-frequency autotransformer are given for the reference of colleagues in the production. The iron core adopts 4kbee ferrite, and the skeleton adopts ee19 vertical skeleton corresponding to the iron core. Its technical parameters are shown in Figure 3

Figure 3 technical parameters of T1 transformer

3.3 working principle of charge discharge circuit

charge discharge circuit is mainly composed of capacitors C7 ‖ C10, C8 ‖ C11, C9 ‖ C12, C13, R14, step-up transformer T2, etc. When capacitors C7 ‖ C10, C8 ‖ C11 and C9 ‖ C12 are charged to the set high voltage value, the voltage in capacitor C13 is also charged to the required voltage value (about 300V). At this time, K1 or K2 is closed, thyristor V3 is triggered to turn on, and the energy stored in capacitor C13 is discharged through the primary winding of transformer T2, causing the secondary winding to induce a high voltage of about 10kV, ionizing the gas in the laser. At the same time of ionization, the energy stored in capacitors C7 ‖ C10, C8 ‖ C11 and C9 ‖ C12 will maintain the ionization process for a certain time, so as to obtain the required laser pulse

4 selection and technical requirements of important components

1) energy storage capacitor since the energy storage capacitors C7 ‖ C10, C8 ‖ C11, C9 ‖ C12 need to provide enough energy for the laser in a very short time, when selecting this capacitor, in addition to requiring it to have a sufficiently high withstand voltage value (≥ 350V), it must also require it to have the characteristics of rapid charging and discharging, that is, it should choose the flash capacitor printed with "photoflash"

2) step up transformer in addition to discharging the power supply capacity C13 of its primary winding to raise the secondary voltage to more than 10kV, the step-up transformer also needs to meet the requirements that when the gas is ionized, all the energy in the capacitors C7 ‖ C10, C8 ‖ C11, C9 ‖ C12 will be released to the laser through the secondary winding, so that it can work hard to cooperate with a decline in the national subsidy policy of vehicle enterprises, and select a suitable model test ejector to excite a strong laser beam. Therefore, the secondary winding should not only have a large number of turns, but also have a small resistance, but also meet the requirements of high voltage resistance. The magnetic core of the transformer is made of ring-shaped 3KB ferrite material, the primary winding is made of 1.0 Teflon silver plated high-voltage wire, the secondary winding is made of 0.32 Teflon silver plated high-voltage wire, and the iron core magnetic ring is made of soft magnetic ferrite with outer diameter of 35, inner diameter of 12 and thickness of 10. Its technical parameters are shown in Figure 4

Figure 4 technical parameters of T2 step-up transformer

3) instructions for max641/642/643 selection

(1) the square wave amplitude output by V2 driven by the PWM signal output by max641 is 5V

(2) the square wave amplitude output by V2 driven by PWM signal output from max642 is 12V

(3) the square wave amplitude output by V2 driven by the PWM signal output by max643 is 15V. (end)

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