Digital Control Application in Push-Pull Converter

• Main Authors: Jen-ming Hsu, 徐仁明
• Other Authors: Ching-Shan Leu
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/38530405115068977468

碩士 === 國立臺灣科技大學 === 電機工程系 === 100 === With the advance in technology, digital controllers are increasingly being used especia1ly in power electronics systems. Therefore, this thesis presents a DSP based digital control design and implementation of a step-up/step-down symmetrical push-pull power converter. The step-up/step-down symmetrical push-pull power converter can reduce input current ripple with clamping capacitors and achieve the function of step-up/step-down with a step-up transformer. The crossover frequency and the desired phase margin can be chosen first. With the help of software SIMPLIS, the open loop Bode plot of the step-up/step-down symmetrical push-pull power converter can be obtain and analyzed. Next, the compensator type can be selected based on the open loop Bode plot. Accordingly, the placements of zero and the pole can be determined. The component value can be calculated by MathCAD. The analog control can be verified by software SIMPLIS. The analog compensator can be converted into difference equation by using the bilinear transformation. Texas Instrument TMS320F28027 DSP is selected to implement the digital control. In addition to the circuit analysis, the analog control and digital control for a step-up/step-down symmetrical push-pull power converter with 36~75 V input-voltage and 48 V output-voltage have been implemented and verified. Keywords: symmetrical push-pull power converter, Analog control, Digital control.