In a digital implementation of the power conversion design, two contributing factors are needed to implement the desired topology and control loop:
- Designers' knowledge on the power conversion topology and the set of equations that describe the topology itself. How the controlled variables (duty cycle, phase relationship, etc.) are influenced by the system parameters. See figure below.
- Real-time data: run-time currents and voltages which need to be measured periodically.
This means that the digital approach operates on the equations and numbers that represent the most up-to-date values of the controlled variables. Some calculations are required to “transform” the input data, through the implemented algorithm, into the output data. The unit that operates this number crunching must be fast and efficient in order to generate the updated values within a short period of time. This allows efficient control of the system. In the next several sections, we'll take a closer look at how the dsPIC® DSC computational core can meet these requirements.