As shown in Figure 1, the three-phase bridge thyristor full-controlled rectifier is applied. The inverter adopts the single-phase bridge inverter circuit. The load adopts the parallel resonant structure. As the large inductor is used as smoothing reactance, the inverter is current-mode inverter. Therefore, over-voltage problem seems extremely important. The company designs a unique over-voltage protection circuit, which plays a vital role in ensuring the safe and stable operation of the inverter. The shoot-through (short circuit) of series resonance and the open circuit of parallel resonance are very dangerousin such circuit with energy storage element. So, what really matters is how to timely detect the fault signal and provide protection. The equipment is not only designed with over-voltage protection circuit from the main circuit, but also equipped with over-voltage timely detection and protection module in terms of control, thereby performing the protection action faster and more accurately and ensuring protection action issued to ensure the safe operation of equipment.
Fig. 1 Diagram of the Structure of Main Circuit of Full-solid-state Inductive Heating Power Supply in GCYP System
