The 20KW medium-frequency induction heating equipment adopts the ZCS circuit to realize high-frequency and low-loss IGBT inversion. Under the control of DSP, it can quickly and accurately track load changes. Parameters such as operation control and limit protection of the device can be set online. The set parameters will not be lost after power off, and the device can be set to resume operation upon power restoration. Applicable to: pre-welding preheating, post-welding