Adopt industrial design standard, high stability and reliability, high efficiency; And off-grid inverter adopts modular design. The system design consists of core control board, auxiliary power board, communication module and power module backplane. The core control board is designed with STM32, and the core controller has 512K Flash, 64K SRAM and 72MHz main frequency. The device is equipped with JLINK interface for user programming and debugging. Communication module adopts high-speed optocoupler isolated communication. The auxiliary power module adopts special PWM control IC design to realize isolated power module to realize dc power isolation and multi-channel power output. OLED display module with liquid crystal and independent keys, can achieve I human-computer interaction; Power base plate with MOSFET power tube and isolation driver module, the module driven by a variety of high frequency transformer to realize power supply isolation, controller backplane dedicated PWM control IC design was adopted to realize closed loop DC booster, DC booster system with DC - AC conversion, AC - AC booster, AC - DC rectifier modules, such as H bridge IGBT power building, and driven by optical coupling isolation, AC output common-mode inductor and capacitor filter.