With the development of pulse power technology, higher technical requirements have been put forward for the pulse power supply system. How to improve the precision of power supply is the hotspot of current research. In this paper, a 20 kJ high-precision pulse power supply is established for study, consisting of a high energy storage pulse power capacitor (6420 μF/2.5 kV), a pulse forming inductor (2.73 μH/0.945 mΩ), a 4 in. thyristor, and 2 4 in. diodes. Three characteristic parameters (current peak Imax, rise time T r, and pulse width T w) are proposed to define the precision of the pulse power supply: Imax = 54 kA, T r = 205 µs, and T w = 1470 µs. According to the electrical parameters, the numerical expressions of the power supply precision are theoretically solved. This can guide the device screening and active temperature control scheme. Then, the active temperature control experiment of the high-precision pulse power supply was carried out. The results show that Δ Imax is less than 1.2‰, Δ T r is less than 1.8‰, and Δ T w is less than 2.1‰, within the ambient temperature of 10–30 °C. The rated [Formula: see text] is different under different ambient temperatures. The extreme difference is 0.7 kA, and the error is 6.5‰. In addition, the life test of a high-precision pulsed power supply is carried out, which shows that the capacitance and inductance will decrease with the increase of rated discharge times. The change of capacitance is 1.19‰, and the change of inductance is 3.73‰. Finally, this high-precision pulse power supply has proved that the precision can reach a thousandth under the condition of active temperature control, and it is proposed that the precision of the power supply can be maintained by controlling parameters such as device temperature and discharge voltage.
