DSP Control Method of Single Phase Inverters for UPS Application  

Abstract:  This paper presents a new deadbeat control solution and a digital control strategy suited for high performance single phase inverters capable of maintaining very low THD of less than 1% in the presence of unknown loads.  The method takes into account the digital model of the PWM inverter and derives a new set of gains for the voltage and current loops.  The current loop gain obtained by this approach is shown to be higher than previously known and this leads to a better disturbance rejection and faster dynamic response.  The control strategy was implemented on a 16 bit fixed point DSP controller (ADMC401) and tested on a 5KVA IGBT based inverter switching at 20KHz.

DSP Control of 400Hz Inverters for Aircraft Applications 

Abstract:  This paper presents a fully digital control method that can be used for inverters applied in 400Hz aircraft ground power units.  The method presents an ideal tracking controller that incorporates the computational delay as well as the quantization effects.  It uses an observer for the output current third, fifth and seventh harmonics in order to achieve decoupling between the voltage and current loops thus leading to a low THD content in the presence of non-linear loads.  The implementation of the observer is reduced to IR filters with normal architecture that have minimum round off errors.  The control method is implemented on a 16-bit single chip DSP-based controller from Analog Devices (ADMC401) and tested on a single-phase 10kva IGBT-based inverter prototype showing almost complete elimination of the third, fifth and seventh harmonics from the output voltage.