Application of Two-Phase Immersion Cooling Technique for Performance Improvement of High Power and High Repetition Avalanche Transistorized Subnanosecond Pulse Generators

Heat management technology for solid‐state high voltage and high repetitive pulse generators: Towards better effects and reliability

“…Under repetitive operation mode, the temperature of the switching devices may fluctuate considerably. Figure 5 illustrates a typical temperature rising process of the junction of an avalanche transistorised HVRPG [51]. Due to the substantial transient power dissipation during switch operation, a peak temperature of a few hundred Kelvin may be reached in the semiconductor junction [52].…”

“…The components' heat dissipation and temperature distribution vary depending on the operating conditions. For example, the inhomogeneous temperature distribution in an avalanche transistorised circuit, has been theoretically modelled and empirically demonstrated [51,65], with a maximum temperature differential of 40°C. This considerable temperature difference will create stress distribution on the board and make it difficult to lay out an effective and uniform heat management technique.…”

“…Two-phase immersion cooling, commonly known as pool boiling, has been successfully used in electronic equipment heat management system [96,97]. The system's electronic components submerge in a tank filled with boiling volatile dielectric coolant [51,98]. The heat produced by the electrical device is efficiently absorbed as saturated vapour, which can then condense and transmit the heat to an external cooling medium.…”

“…As shown in Figure 12, Wang et al developed a passive two-phase immersion cooling system for a high voltage, high repetition rate subnanosecond pulse generator based on avalanche transistorised Marx circuit. The PCB board is placed in the aluminium vessel and immersed in the dielectric liquid [51]. To reduce coolant leakage, a tightly-fitting aluminium plate is installed on top of the vessel.…”

“…While the time base jitter and voltage amplitude jitter are both proportional to the operating temperature, a coolant with a low boiling point might be used to accurately control the device temperature within the ideal temperature range. It should be noted that the high dielectric F I G U R E 1 4 Photograph of the bubble state of several boiling stages under different frequency [51].…”