The Design Of Traveling Wave Tube Power Supply System

TWT is mainly used in radar, electronic warfare equipment, satellite communications and other fields, which is an essential component in the development of high-tech weapons. And a set of dedicated power supply is exceedingly needed to ensure the TWT operates smoothly. The power supply’s function parameters would affect the work condition of the traveling-wave tube directly, and because the different TWT types require different power supply modules, the development of traveling-wave tube’s high-voltage power is merely a kind of customized power supplies, which has not been commercialized yet. Currently, high voltage power supply module of TWT is so dependent on imported that to develop a high adjustable voltage power supply of traveling-wave tube becomes more significant. The thesis topic comes from a cooperating development project with a domestic power company.In this paper, high voltage power supply system consists of four independent high functional modules, which reduce the coupling of each power supply module among the separate traveling-wave tubes and eliminates the design of the power supply system depending on the power mode of TWT accordingly.In this paper, the high voltage power system design is determined with the technology of high-frequency switching power supply as the theoretical basis, and the technical indicators as a breakthrough point. The design process is demonstrated elaborately, and the final test results are coincided with the desired targets.The major power-transfer module mainly introduces the selection of core structure,the explicit calculation process of the parameters designation, the actual design parameters in practical engineering; and the corresponding insulation treatment measures. The full bridge soft switching converter is used for major high-voltage power converter module, and the resonance is realized by means of capacitance and inductance in the circuit, thus to achieve the conduction of IGBT at zero voltage.The main drive conversion module also provides over-current protection circuit.Assist control portion helps to achieve the digital control of voltage regulation and phase shifting with the combination of STM32 and traditional PWM chip UCC3895. The output voltage can be set via the LCD touch screen and the STM32 can read the corresponding digital control commands from it, and send them to the PWM chip, then outputs the PWM signal and generates high voltage. Comparing theSTM32 digital control outputs, which is regarded as the reference signal, with the sampled voltage’s feedback signal, then adjusting the size of the phase shift angle through the internal circuit structure of UCC3895, the duty cycle of the output PWM can be controlled, which leads to adjusting and stabilizing the voltage digitally. Also a signal detection circuit and a corresponding software program are designed for STM32 to monitor the work condition of entire power. When the over current or voltage outputs are detected, it will start instantaneously protective programs, and disconnects the PWM output simultaneously.Parts of circuit parameters are modulated after the repeated trials in debugging process, thus achieving the anticipations. The design of TWT high power supply is characterized as the large adjustable output voltage range, the high precision and the small ripple etc.