This paper presents a fully digital multiple-loop control scheme for the regulation of PWM inverters used in uninterruptible power supplies (UPS). The proposed digital control scheme incorporates an outer voltage loop with an inner current loop to regulate the output voltage of the PWM inverter. The digital controller is designed using deadbeat theory so that the inverter can achieve fast dynamic response. To enhance the robustness of the PWM inverter, an output voltage decoupling mechanism is proposed to improve the performance of the inner current loop. Furthermore, a load disturbance compensation scheme is also developed to remedy the voltage distortion caused by load variation. Both the frequency-domain and time-domain behavior of the proposed control scheme are examined in this paper. A PWM inverter control system based on DSP TMS320C14 was constructed to verify the designed control law. The simulation and experimental results show that the output voltage of the controlled PWM inverter has little distortion even under rough load conditions.
|Number of pages||8|
|Journal||Proceedings of the National Science Council, Republic of China, Part A: Physical Science and Engineering|
|State||Published - 1 Sep 1997|