Research On Power Factor Correction Technology And Its Controller Chip Design

With the rapid development of power electronics, the capability of utilizing electricity and the performances of electric network have been greatly improved. But due to wide applications of the rectifiers, various harmonic waves are produced. They pollute the electric network seriously and reduce the efficiency of production, transmission and utilization of electricity. Recently, the energy shortage has become the bottle neck of developing national economy. Since the power factor is of key importance to raising of energy efficiency and improving of performances of the electric network, new rectifiers with high performance are in dire need, which have the power factor correction function to restrain the harmonic waves of switch power supplies.Research on the power factor correction technology in switch power supplies is internationally focused on the circuit topology and the control circuit. In recent years the power factor correction technology are developed rapidly, which have become an important field of power management IC. Now the power factor of modern switch power supplies with power factor correction function can be raised to 0.95~0.99, near unit. Compared to the technology progress overseas, the research on power factor correction IC (integrated circuit) in our country is just started up. It is partly due to the restriction of the domestic IC process required for these IC. The requirements of high voltage and large driving capacity made it difficult to develop these.In this thesis, the recent power factor correction technologies were widely disscused. And the enhancement of power factor pre-regulator (PFP) system was introduced by improving the average current mode control. An input voltage feed-forward part was added to the control loops to improve the system stability while the input voltage varied. For the use of active power factor correction technology of modern power electronic appliances, a controller chip was proposed based on the BCD (Bipolar-CMOS-DMOS) process with an average current mode control and a feed forward voltage. The whole design was fulfilled including system design, circuit module design and layout design. A solution using macro model was introduced to settle the difficulties in system simulation of high frequency switch power supplies. A 250W Boost converter circuitry based on the chip was simulated. The results showed that the THD (Total Harmonic Distortion) of its output current was reduced to 1.7% and the near unity power factor was available, when the input voltage is 220V, 50Hz. Soft start up and the protection functions including the under and over voltage protection and the over current limit were realized perfectly. And the power dissipation is 0.11W (including switching loss) when supply voltage is 12V. The designed chip was taped out. As results, the thesis gave the detailed testing results, which show that the chip works normally and the specifications meet the designed Spec. well.