Co-simulation PSIM-ModelSim oriented to digitally controlled switching power converters

Digital controllers based on specific hardware (FPGA or ASIC) described in hardware description languages (HDL), such as VHDL or Verilog, have been applied to low or medium DC/DC switching power converters in the last years. Standard designs procedures of DC/DC power converters involves the simulation of the whole converter, including analog power stage and digital control stage. Co-simulation of both parts, modeled in their native simulation environment is not evident, since it requires the cooperative operation of an analog simulator and a digital simulator with HDL capabilities or a mixed-signal simulator. In this paper a true co-simulation procedure between PSIM (specially oriented to power electronics) and ModelSim (extended VHDL-Verilog simulator) is presented. Co-simulation is achieved by means of a communication interface between both programs. It has been applied to the co-simulation of DC/DC switching power converters. Results show the validity of the presented approach. One of the main advantages of the co-simulation is the ability to use accurate and tested models of power stage, and the real designed digital controller that will be synthesized in the FPGA.