OCP或SCP–這是個問題！

　　通常情況下，許多不同類型的保護功率晶體管，電機或任何部分的系統(tǒng)所需的電機驅(qū)動應(yīng)用。逆變器的電流保護是至關(guān)重要的項目之一。它不僅防止功率晶體管的任何潛在的損害，但也退磁電機故障發(fā)生或控制變得不穩(wěn)定的情況下。過電流保護（OCP）和短路保護（SCP）通常是類似的，但又有區(qū)別，本文將討論的問題。

　　.OCP和SCP之間的差異

　　簡單地說，短路保護是過電流保護的一部分。圖1顯示了不同的電流保護之間的關(guān)系。接地故障保護，ARM短路保護，相間短路保護均屬于短路保護。

　　Figure 2 shows the different short-circuit modes and their current path. As illustrated in Figure 2（a）， ground fault occurs when the motor winding gets shorted to the motor frame， which is typically connected to the earth ground， or sometimes when a motor cable gets shorted to the earth ground. Figure 2（b） shows arm short which refers to the case when both the high-side IGBT and the low-side IGBT turn on accidentally at the same time and very-high current flows as a consequence. Figure 2（c） depicts a phase-to-phase short which happens when motor windings from different phases get shorted. In all three cases， the magnitude of current is limited by the impedance of its current path， including the IGBT itself.