Research On Current Sampling And Power Factor Correction Of The Small Inverter

The development of power electronics, automatic control theory, microelectronics technology has played a great role in the improvement of AC inverter technology. Motors, the important tool to convert the electrical energy into kinetic energy, consume a huge proportion of the electric energy consumption. Variable frequency speed control is a important technology in motor control. It has great social and economic benefits in today's energy shortage. Now many countries think highly of the development of the inverter technology. They try their best to reduce the costs on the basis of the good control performance to improve the competitiveness of products. Our country has a large population, the inverter has a broad market, so we should improve the competitiveness of our products.Now the vector control without speed sensor technology has been more applicated, it reduces the cost of the inverter. But it needs to install the current sensor or other methods to sample the current of the motor. The use of large household appliances caused a large number of harmonic pollution, it needs the inverter system to correct the power factor. Now most products solve the problem with the special chip for APFC.This paper use a bus resistor to reconstruct the three-phase current for the problem of that the current sensor increases the complexity and cost of the product. Reconstruct the motor phase current on the basis of the analysis to the corresponding relationship between the bus current of the inverter and the motor phase current. It saves the current sensor and hardware resources, reducing the system cost. Then do the simulation and experiments with Matlab software and DSP chip, and get the good result. Research the PFC technology for the problem of the traditional active power factor correction needing a separate APFC chip. Using a new method to correct the power factor on the basis of analyzing the current circumstance when the IGBT turned on. Reduce the system cost and get a good experimental results.