Application Of LCC-SPRC Working In Continuous Current Mode For High Frequency Electrostatic Precipitator

High-frequency electrostatic precipitator which has the advantages of small size, high efficiency and high collectable efficiency, becomes the focus of extensive research in the industrial dust area. Previous high-frequency electrostatic dust power supply works in the discontinuous current mode. Switch achieves soft switching in the whole work process, it decreases the switching loss. However, due to the high peak current of the resonant circuit, the large conduction loss is not conducive for the expansion of power supply. The operating characteristics and control system of high-frequency electrostatic precipitator working in the continuous mode are described in the article.Firstly, the article introduces the three PS-PWM control mode and their respective advantages and disadvantages of LCC resonant converter in the continuous current mode. An optimal control mode, which works between F-type and M-type, is proposed after that. Conduction losses in the power switches and in the resonant components, and switching losses can be minimized. The output voltage expression of optimal control mode has been obtained based on the mathematical model with the fundamental analytical methodology. The equivalent mode is used to design the main circuit parameters of LCC resonant converter. Then the paper gives the characteristics of different output voltage of the circuit, and compare them with the circuit in the discontinuous current mode.Secondly, a phase-locked method is used to realize the optimal control mode. The principle of the phase-locked loop is described. For the shortcomings of analog PLL, the paper proposes a digital phase-locked method which bases on the ECAP module of DSP. The control system is simple and reliable. The prototype is used to verify the feasibility of phase-locked control system.Thirdly, the paper analyzes the flashover control of the electrostatic precipitator. The closed-loop feedback control of the output voltage is the basis of flashover control. The circuit adopts the incremental PI control algorithm to accomplish the control of the output voltage. The control system checks the signals of the output voltage and output current to measure the occurrence of flashover. Segmented control algorithm makes the output voltage track the dielectric recovery curve, and realizes the control of the rate of the flashover.Finally, a conclusion about the content of this article is made and the future work is put forward.