DSP IMPLEMENTATION OF A REAL-TIME BOOST CONVERTER SIMULATOR HANDLING INTER-STEP SWITCHING DELAY

Abstract

This paper introduces the development and implementation of a boost converter real time simulator dealing with inter-step switching delays, which occur due to the different time steps and resulting asynchronism between the digital controller that outputs switch ring signals and the microprocessor that simulates the boost converter. It is shown that, if left unaccounted for, these delays can cause inaccuracy levels such as to make both closed and open loop simulations unreliable. In order to avoid this, a time step changing algorithm is implemented. This algorithm is based on the detection of switching orders and a subsequent correction routine to account for the delay by calculating the system state at the detection moment. The boost circuit is modeled through the differential equations of each possible converter state-conguration (that is, each mode of the circuit). The equations are then numerically solved by Backward Euler method. The real-time platform is composed by two Texas Instruments DSPs, the rst one simulating the converter and the other mplementing the Proportional-Integral control system. The implemented algorithm works as intended and allows for an increase in the converter simulation time step to values which would previously give incorrect results.