CC-PFB401 51405044-175 Continuity Current Diode

CC-PFB401 51405044-175 The transient voltage generated when the current flowing through the IGBT is cut off during the turn-off transient. It is due to the inductive load with motor (L) and leakage inductance (Lp) in the circuit, the total value of L * p = L + Lp then Vp * = Vce + Vp and Vp = L * p di / dt in extreme cases will produce Vp * Vces (rated voltage) resulting in damage to the device occurs, in order to take as much as possible to reduce the inductance (L), the leakage inductance (Lp) in the circuit. -By the device manufacturing structure, such as reasonable distribution, shorten the length of the line, appropriate widening and thickness reduction.

CC-PFB401 51405044-175 is for when the lower arm of the IGBT off, inductive current can be in the upper arm of the continuity tube to provide access, (this time at the positive conduction), it will reduce the di / dt value, to prevent overvoltage. But also when the lower arm conduction, the continuity diode reverse recovery, become negative and shut down, the current will fall to zero value, due to the presence of Lp to generate surge voltage, prevent the current from falling, especially when the use of hard recovery diode, will produce a high reverse recovery di/dt value, can lead to a very high transient voltage.

CC-PFB401 51405044-175 is used to control the turn-off surge voltage and the recovery surge voltage to reduce the switching losses of the module and the transient overvoltage values employed. Although the IGBT has a strong switching safety operating area, but the need to control the transient voltage value, and buffer circuits in each switching cycle can be discharged through the IGBT, so there is a certain amount of power consumption, but to ensure the safety of use.