AC/DC Flyback Converter with a Single Switch Controlled DC Motor Drives

In this paper a simplified approach for speed control of a separately-excited DC motor using single-phase, single-way rectifier is presented. This approach is based on the cascade combination of a diode bridge rectifier and flyback converter. Step-down and step-up characteristics of the output voltage can be obtained. The supply current is approximately sinusoidal with a high power factor. A high performance is achieved with a ripple free for the output voltage and current. A digital signal processor (DSP-dspace1102) board is used to implement the converter in open and closed-loop system. The proposed system modeling and simulation are performed using the differential equations describing the system behavior in different modes of operation. The proposed program is a powerful tool to predict and describe the system behavior in starting, transient and steady-state conditions. The effect of the duty-ratio on the motor performance characteristic is investigated. The speed control with proportional integral controller is designed and the controller parameters are obtained to satisfy the best system responses for load disturbances. The simulation results are given and prove a good agreement when compared with experimental results