IDEALPLUSING High-frequency multiple high-voltage pulse power supply for dust collector

      Electrostatic precipitator has a development history of more than 100 years. It is the preferred product for industrial dust removal equipment because of its unique advantages such as high dust removal efficiency, wide adaptability, low operating cost, safety and reliability, easy use and no secondary pollution. Faced with increasingly stringent emission standards, many in-service electrostatic precipitators cannot meet the requirements and have to undergo secondary technical transformation; new electrostatic precipitator projects to be built also face challenges. Although lengthening and heightening the electrostatic precipitator body can improve the dust removal efficiency accordingly, the cost-effectiveness of equipment investment and dust removal efficiency improvement is low, and conventional improvement methods are difficult to meet new environmental protection standards. The new high-voltage power supply has become an effective way to improve the efficiency of electrostatic precipitators. The promotion and application of three-phase industrial frequency high-voltage power supply, high-frequency high-voltage power supply and pulse superposition DC high-voltage power supply have provided new possibilities and new options for improving the efficiency of electrostatic precipitators.

Power supply introduction

      High-frequency multiple high-voltage pulse power supply for electrostatic precipitator (referred to as high-frequency pulse power supply) is a power supply for electrostatic precipitator that can provide both direct current (DC) power supply and direct current superposition pulse (DC+PULSE) power supply.

      The voltage superposition of high-frequency pulse power supply can combine and output a variety of secondary voltage power supply waveforms. The multiple controls of the electric field effective corona voltage superimposed on the pulse voltage (DC+PULSE) make the effective value, peak value and frequency of the secondary voltage adjustable. The control method is flexible and can adapt to various working conditions of electrostatic precipitators.

      The electrostatic precipitator is powered by a high-frequency power supply, which is a DC voltage of the same amplitude that continuously charges and pressurizes the precipitator, so that the plate line is always maintained near the breakdown voltage point. When the dust resistivity exceeds 1011Ω·cm, problems will occur in the process of gas ionization-dust charging-movement-capture-dust removal. When high-resistance dust accumulates on the anode plate, due to continuous pressure, the neutralization speed of the charged dust on the anode plate is recharged faster, resulting in the thickening of the anode plate dust layer and the increase of the surface potential, resulting in a relative decrease in the potential difference to the discharge electrode, and the weakening of the discharge electrode corona discharge, causing the back corona phenomenon to occur, and the dust removal efficiency is greatly reduced.

      The dust collector uses a high-frequency pulse power supply: pulse power supply (DC+PULSE) is in the form of superimposing a pulse voltage while continuously charging and pressurizing the dust collector with an effective corona voltage. This charging method not only increases the instantaneous charging voltage, but also reduces the average charging voltage. Even for high-resistance dust, the potential in the dust layer can be easily neutralized on the anode plate, and the surface potential of the anode plate is reduced, which will not increase the relative potential with the discharge electrode, thereby suppressing the occurrence of the back corona phenomenon. The instantaneous high voltage of the pulse wave makes it easier to charge the dust, so the dust removal efficiency is greatly improved.

       The high-frequency pulse power supply integrates multiple power supply modes into one, which can realize DC power supply, intermittent power supply, and DC superimposed pulse power supply. The pulse voltage is superimposed on the effective DC corona voltage to realize step pulse power supply, which has the characteristics of fast pulse front time. During the fast pulse front time, an instantaneous high-intensity electric field is generated, and the electron charging mechanism of particles in the pulse discharge corona field is mainly based on the electric field charging and kinetic energy diffusion charging of electrons. In order to charge particles quickly, it is effective to use a pulse with a fast pulse front. The charge of dust charged by free electrons is more than 50% higher than that of dust charged by ions. High-voltage pulses can increase the peak voltage of the electric field, which not only increases the instantaneous electric field strength, but also stimulates a large number of free electrons. The effective DC corona voltage maintains the corona voltage of the electric field, which ensures the driving speed of the charged dust and reduces the surface potential of the dust layer on the anode plate, thereby curbing the occurrence of the back corona phenomenon to the greatest extent, and greatly improving the adaptability of the electrostatic precipitator to complex working conditions such as high resistivity dust and high concentration dust. On the premise of meeting the dust emission standards, energy-saving control can be achieved by adjusting the step pulse power supply waveform.

Features of high-frequency multiple high-voltage pulse power supply for electrostatic precipitator

      (1) Green power supply: three-phase power supply, grid balance, no harmonic interference, high power factor, and high power conversion efficiency.

      (2) Multi-voltage superposition technology: multiple groups of IGBT full-bridge inverter power units are combined to achieve power superposition and voltage superposition of high-frequency pulse power supplies such as 2+1, 3+1, and 4+1. Multi-voltage superposition can combine any voltage waveform shape, output a variety of DC voltage waveforms and DC+PULSE voltage waveforms, and realize pure DC power supply, intermittent power supply and pulse power supply for the electrostatic precipitator. The voltage peak and effective value are adjustable, and the electric field control method is flexible.

       (3) High-frequency narrow pulse: The output frequency range is 2kHz-40kHz. The electrostatic precipitator is a capacitive load. The higher the power supply frequency, the smaller the electric field capacitive reactance, and the greater the energy injected into the electrostatic precipitator by the power supply. The pulse width is 8uS, which is more conducive to the generation of instantaneous high-intensity electric field and the agglomeration of fine dust.

      (4) Intelligent control: After the DC+PULSE secondary voltage waveform is set, the equipment automatically tracks the critical point of the electric field breakdown voltage by adjusting the frequency. The electric field is not easy to flash over, and the optimal power output is achieved.

      (5) Closed-loop energy control: According to the closed-loop control between the dust collector emission concentration and the power consumption of the electrostatic precipitator power supply, energy saving and emission reduction are achieved. The system is optimized and controlled by the upper computer network.

      (6) Voltage reduction and vibration control: It has the function of back corona detection. When back corona occurs, it outputs a linkage signal to timely reduce voltage and vibrate to clean dust.

      (7) Capture of fine dust: The emission of fine dust is a key indicator affecting the dust emission concentration of electrostatic precipitator. The instantaneous high-intensity electric field corona generated by high-frequency narrow pulse power supply greatly improves the capture of PM2.5 and below particles.

      (8) Capture of high-resistance dust: When DC+PULSE power supply is used, the occurrence of back corona phenomenon is curbed to the greatest extent, greatly improving the capture effect of high-resistance dust.

      (9) Desulfurization and denitrification: The instantaneous high-intensity electric field corona generated by high-frequency narrow pulse power supply is more conducive to the increase of ozone concentration and the efficiency of desulfurization and denitrification.

      (10) Energy saving and emission reduction: Compared with conventional single-phase industrial frequency power supply, high-frequency pulse power supply improves the dust removal efficiency of electrostatic precipitator by +50% and reduces electricity charges by -30%.

      (11) Overall structure and protection: High and low voltage integrated assembly, outdoor layout, saving the construction area of the control room. The heat dissipation of power devices such as IGBT adopts box-type isolation duct to isolate the power devices and control unit board from the external environment. The heat dissipation system adopts intelligent control of speed-adjusting fans to improve the adaptability of high-frequency pulse power supply in outdoor high-temperature environment. The control unit board adopts three-proof process treatment to improve insulation and corrosion resistance. Stainless steel shell, protection level IP54.

      (12) Protection function: spark flashover, electric field open circuit, electric field short circuit, overload, undervoltage, IGBT temperature, transformer oil temperature, oil level, equipment failure and communication failure, etc.