The platform adopts a distributed multi-simulator collaborative architecture: one master simulator simulates the front-end cascaded H-bridge circuit in real time with a 1 μs time step, while three slave simulators accurately simulate the back-end high-frequency DC-DC converters of each phase with an extremely small 100 ns time step. Real-time data interaction between the four simulators through fiber, together with clock synchronization lines ensuring strict synchronization, forms a high-precision, unified virtual controlled plant.

At the communication and interface level, to achieve the highest signal authenticity, the SST front-end communication interface design principle is: the master simulator sends data to the front-end electro-optical signal conversion boxes through high-speed fiber. The conversion boxes are divided into a DI (digital input) electro-optical conversion box and an AO (analog output) electro-optical conversion box; the former converts the real physical level signals of the sub-controllers into fiber signals output to the power electronics switch model in the master simulator; the latter converts simulated analog quantities such as sub-module capacitor voltages into high-precision physical analog voltage signals output to the sub-controllers. The SST back-end communication interface design principle: the slave simulators interact directly with the corresponding sub-controllers through physical I/O. Thus, at the end of the signal chain, the test platform fully reproduces the electrical connection characteristics and signal timing between real power equipment and controllers, building a high-precision, high-fidelity hardware-in-the-loop test system suitable for final product certification and high-reliability verification.