Sensorless Control for Three-Level Boost-Type Switch-Mode Rectifier

• Main Authors: Liao, Jhen-Yu, 廖振宇
• Other Authors: Chen, Hung-Chi
• Format: Others
• Language: en_US
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/72162797353860951290

博士 === 國立交通大學 === 電控工程研究所 === 102 === There are many nonlinear loads connected to the grid. These nonlinear loads will increase loss in power transmission line. Therefore, power factor correction function is proposed for improving power factor. Buck, boost, and buck-boost converter are popular for PFC Boost-type is a popular topology for PFC. A three-level boost-type switch-mode rectifier (SMR) is used for PFC in this dissertation. The three-level boost-type SMR has advantages of low voltage stress for switch and low current ripple. Nevertheless, the three-level boost-type SMR has to sense more signals than boost-type SMR to balance two capacitor voltages, which would increase cost and size for the system. Therefore, this dissertation proposes two sensorless controls for the three-level boost-type SMR. The two sensorless controls are capacitor voltage sensorless control (CVSC) and inductor current sensorless control (ICSC). The multiloop interleaved control is also proposed. The multiloop interleaved control senses input voltage, inductor current, and two capacitor voltages. The multiloop interleaved control has a corrector which can avoid current distortion at zero crossing point when the loads are asymmetric. The multiloop interleaved control is able to work well in three cases- single load, symmetric loads, and asymmetric loads. CVSC only does sense input voltage, inductor current, and output voltage of the three-level boost-type SMR. CVSC samples the inductor current at some specific points to balance two capacitor voltages. The sampled current points can be used to judge whether two capacitor voltages are balanced. Nevertheless, CVSC has some limitations. From the analysis of CVSC, the proportional gain for balancing two capacitor voltages has to limit in some region. It cannot work in the case of asymmetric loads. But it is able to work well in the case of single load and symmetric loads. ICSC only does sense input voltage and the two capacitor voltages of the three-level boost-type SMR. The ICSC also has a corrector which can avoid current distortion at zero crossing point when the loads are asymmetric. ICSC is suited in the case of single load, symmetric loads, and asymmetric loads. Some simulations and experimental results are provided to verify the proposed multiloop interleaved control and two sensorless controls. All simulations and experimental results are operates at CCM. The load of the three-level boost-type SMR is a resistor.