A fault tolerant digital controller for power electronic applications

In safety critical applications, fault tolerant controllers are very important. In this paper a generalized fault tolerant digital controller for power electronic applications is presented. Three fixed point digital signal processor (DSP) based controllers are used in parallel, running the same control algorithm. The PWM outputs of three DSPs are voted out to one PWM output using a simple fault tolerant majority voting logic. The fault tolerance of digital control system is verified using field oriented control (FOC) for a permanent magnet synchronous motor (PMSM).