Abstract: Small time-step real-time simulation is the key to hardware-in-the-loop testing of power electronic converters. Considering the loss can make the real-time simulator response closer to reality, and effectively evaluate the efficiency. Small time-step model based on the equivalent of inductance/ capacitance has virtual loss problem, and cannot simulate the loss accurately. This paper proposed a model that reflects the loss characteristics, combined the equivalent of physical components and discrete system constructed, obtained the parameters through response matching, and gave the stability region. For the inconvenience in switching loss real-time simulation, an equivalent algorithm with high versatility was proposed by promoting the impulse theorem. The simulation and experimental results show that, compared with the LC-based model, the proposed model and algorithm suppresses distorted switching oscillation, eliminates off-state losses, greatly improves dynamic and steady characteristics, and has higher accuracy of loss simulation.