Analysis of Transient Voltage and Protection from Thyristor Commutation

As well known, components of the thyristor own high resistance and low capacity, which limits its abilities of storing and dissipating the energy caused by overvoltage. Therefore, some means must be adopted to keep the device operate safely. The article analyses reasons of transient overvoltage in thyristor based converter and schemes of protection, and points out the main reason of cause of spike, and further provides the method of choosing the parameters of protective circuit to deal with commutation spike, finally gives an example in detail.