Research On Digital Controlled AC/AC Chopping Converter

The AC/AC voltage regulator with chop-control techniques are the hotspots of power electronics research. Industry standard for the control of AC/AC switch systems has been analog control for a long time. Now with the advent of high speed, lower cost digital signal processing (DSP) ICs, there has been an increased interest in digital control of AC/AC switch. Digital control provides advantages such as programmability, less susceptibility to environmental variations and fewer part counts. It also reduces the size of power supply by containing the complexity of control system within the software. Therefore, digital control is becoming lower cost and more applicable for intelligent control.The chopping mode AC/AC conversion is a new AC voltage control technology which is based on the self-commutated switch and the Pulse-Witch-Modulation (PWM) control method. The new type Phase-Shifter based on this technology can overcome the faults of the line-commutated thyristor Phase-Shifter, such as the amount of low-order harmonic injection, the operation of its control circuit is limited by the condition of the network, and so on. In addition, it also has the advantage of fast response, flexible adjustment and easy control. The main research work for the new PWM Phase-Shifter in this dissertation is listed as follow:This thesis analyses the principle of realization the AC/AC voltage regulator with chop-control and advantages and disadvantages of some typical circuits. Based AC/AC PWM converter, state-space theory is used in the state-space model of its topology by incorporating the effects of the circuit parameters.This paper analyses the system control loop to satisfy the performance of the converter. The paper also presents some improvements of main circuit design and the implementation of digital control scheme.The hardware structure of PWM digital control system is simple and realizable. The software of it is easy, highly programmable and reliable. The improvement of main circuit design is correct and satisfies the design demands of practical converter device. It is also indicates the correct of the choose plan.