The use of HVDC systems has expanded with the increasing interconnection of power systems. However, this progress has also made systems more complex. Various simulation methods are employed to simulate and understand these complex interactions in research, development, and testing. Because simulation and analytical methods for HVDC systems and grid converters have diversified, selecting the appropriate method based on understanding their advantages and limitations is crucial for efficient research and testing. This paper reviews model-based development and various simulation techniques that bridge the gap between computer simulations and experiments, clarifying their differences, advantages, and disadvantages.