Design Of A High Voltage High Frequency Power Supply For Electrostatic Precipitators

ESP is the one that apply cement, electricity , metallurgy administration waste gas and environmental protection machinery of the dust of trade extensively, it has very remarkable effect to the treatment of the waste gas and dust, with the increasing request of environment protection, efficiency and energy-conservation operate need to be improved. Today's low-cost, high-performance digital signal processor (DSP) controllers and high frequency switch power supply technology provide wide development space to ESP.This paper analyses the basic principle of electrostatic precipitation and the ESP's request for power supply, designs the system structure of high frequency switched mode power supply for ESP. The whole system is made up of main circuit and control circuit. The main circuit includes rectifier filter circuit, dc-to-ac converter, step up transformer and high voltage rectifier circuit, the core component of main circuit is dc-to-dc converter, and the high frequency power transformer made of amorphous materials can greatly improve the efficiency and minish its volumes compared with traditional ferrite material. The phase-shifted bridge has found many applications due to its distinct characteristics; it permits all switching devices to operate under zero-voltage switching by using circuit parasitic such as leakage inductance and power FET junction capacitance to achieve resonant switching. This paper takes ZVS PWM phase-shifted bridge topology, its power semiconductor is IGBT module, and the phase-shifted PWM signal is generated by EV modules of TMS320LF2407 serial DSP instead of analog control and the control is more flexible.The control circuit includes main control unit and PWM unit. In order to carry out the digital control strategy, we using TMS320LF2407 serial Digital Signal Processor (DSP) of T1 as controller. This controller sample input dc voltage, AC voltage and current of the transformer, then calculate and generate phase shift PWM signal at real time, in the end drive MOSFET of phase shift bridge by drive circuit to achieve control phase shifted bridge. The experiment results show that applying the proposed approach to control the converter above is not only feasible, but also can implement this control strategy very well.