Research on a Self-balancing Pulsed AC Corona Ionizer

Corona ionizers are widely used in semiconductor industry to eliminate static electricity and reduce static damage. In order to improve the speed and ability of Corona ionizers, a pulsed AC corona ionizer which can automatically balance positive and negative ions is studied. In this paper, the composition and working principle of the ionizer are introduced, the main circuit of the voltage doubling rectifier circuit technology and the control circuit using STM32F103CBT6 as the control core are established. The main program, PWM generator an PI control algorithm software were designed. On this basis, the experimental platform of Corona ionizer is built and verified by experiments. The results shows that the peak value of the high-voltage power supply reaches 9.44 kV. When the ionizer works at the frequency of 50 Hz, the distance of 30 cm, and the airflow pressure of 0.1 MPa, the decay time is less than 1.4 s and the offset voltage is less than ±5 V. The amplitude and duty cycle are automatically adjusted to rebalance the positive and negative ions while the ionizer is in a non-equilibrium state. The designed ionizer has short electrostatic elimination time, good ion balance, and can automatically calibrate the ionizer balance state to reduce electrostatic damage.