Multi-level power converter state monitoring system and power device loss calculating method

The invention relates to a multi-level power converter state monitoring system and a power device loss calculating method. The multi-level power converter state monitoring system comprises a system controller, a gate pole voltage synchronization sampling module, a collector-emitter voltage/current synchronization sampling module, a bottom plate temperature sampling module, and a driving signal trigger and blocking module. The power device loss calculating method comprises the following steps of calculating an IGBT on-state loss, an IGBT open loss, an IGBT turn-off loss, a freewheel diode on-state loss and a freewheel diode reverse recovery loss; and through an IGBT internal thermal model, calculating a temperature rise condition of each layer. In the invention, state parameters of a power device in a multi-level power converter can be collected in real time, a problem of the power device is timely discovered and processed, the multi-level power converter is guaranteed to safely and reliably work, calculating