Revisiting Numerical Integration Methods for Digital Implementation in Power Electronics Applications

Digital control systems are vital to power electronic applications because of their flexibility and reconfigurability features. The controller is typically designed in s-domain and is later transformed to z-domain using traditional numerical methods such as forward Euler, backward Euler, and Tustin approximations. In this paper, higher-order numerical methods, namely Adam-Bashforth’s third- and fourth-order methods for integration, are discussed. The associated errors and stability aspects are discussed. The constraints and limitations of z-operator-based resonant controller at a very high sampling frequency are presented. These limitations are addressed using $\delta-$operator-based resonant controller. A nested sub-routine to implement these sub-controller blocks based on priority is discussed. These numerical integration methods are validated on TMS320F28379D DSP-based digital launchpad.