RU94026258A - METHOD FOR REGULATING PULSING DC - Google Patents

Claims (15)

1. The method of controlling the pulsating direct current supplied to the electrodes in an electrostatic precipitator containing discharge and collector electrodes between which a high alternating voltage is maintained, characterized in that the frequency, pulse charge and / or pulse duration of the pulsating direct current is forced to vary so as to obtain many combinations of frequency, charge and pulse duration, and for each of these combinations measure the voltage U between the discharge and collector electrodes, for each combination determine the level U _{re f} , measured or computational, for each combination or integral

measure or calculate a specific time interval, or A _i = U _i • (U - U _{r e f} ) measure and calculate at a set of time points i in a certain time interval, and i _k or linear combinations A _i are used to select a combination of frequency, charge and duration of pulsating direct current. 2. The method according to claim 1, characterized in that establish a reference voltage U _{r e f} as equal to the ignition voltage of the corona discharge. 3. The method according to claim 2, characterized in that the reference voltage U _{r e f} is determined by measuring the upper level, lower level, average level and / or to some extent a certain voltage level U for some different pulse currents at the same frequency pulse frequency, moreover, this level or corresponding levels are expressed as a function of the square root of the current I through an electrostatic precipitator, the function or functions are approximated by expressions of the first degree, and that by a voltage for which two of the functions have the same current or the voltage where one of the functions crosses the voltage axis is selected as the reference voltage U _{r e f} . 4. The method according to claim 2, characterized in that U _{r e f} is determined by measuring the upper, lower, average voltage levels U and / or several certain voltage levels for some different ripple currents at the same pulse repetition rate, this the level or corresponding levels are expressed as a function of current I through an electrostatic precipitator, the function or functions are extrapolated due to low current levels, and the voltage for which two of the extrapolated functions have the same current, or voltage, where one of the extrapolated of the given functions, the voltage axis crosses, choose as the reference voltage U _{r e f} . 5. The method according to claim 2, characterized in that U _{r e f} is determined by measuring the upper and lower voltage levels for some different pulse currents of the same pulse repetition rate, the upper and lower levels represent the values of the current I through the square root function an electrostatic precipitator, the functions being approximated by expressions of the first degree, the voltage for which the functions have the same current is selected as the reference voltage U _{r e f} . 6. The method according to claim 2, characterized in that U _{r e f} is determined by measuring the lower voltage level U for some different pulse currents at the same pulse repetition rate, the lower level being represented as the square root of the current I through an electrostatic precipitator, the function is approximated by expressions of the first degree, the voltage for which the function crosses the voltage axis, that is, the voltage at which the current is zero, is chosen as the reference voltage U _{r e f} .  7. The method according to any one of claims 1 to 6, characterized in that a certain time interval is set equal to or substantially equal to the time during which a corona discharge occurs during a current pulse.  8. The method according to any one of claims 1 to 6, characterized in that a certain time interval begins when the current pulse begins. 9. The method according to any one of claims 1 to 6, characterized in that a certain time interval ends when the resistance R of the electrostatic precipitator, determined by the discharge function
U _x = U _y • exp [(t _y - t _x ) / (R • C],
where C is the capacity of the electrostatic precipitator, which exceeds this level. 10. The method according to any one of claims 1 to 6, characterized in that a certain time interval ends when the resistance R of the electrostatic precipitator, determined by the discharge function
R = - U / (C • dU / dt),
where C is the capacity of the electrostatic precipitator, which exceeds this level.  11. The method according to any one of claims 1 to 6, characterized in that a certain time interval ends when the voltage U drops below a certain level or decreases from the upper level by a given amount of difference between the present upper level and the present lower level.  12. The method according to any one of claims 1 to 6, characterized in that the interval ends when the next current pulse begins. 13. The method according to any one of claims 7 to 12, characterized in that U _{i is} measured, and A _{i is} calculated at time points that are evenly distributed during a certain time interval. 14. The method according to item 13, characterized in that calculate the average level A _m for A _i in the time interval and choose a combination of frequency, charge and duration, which thus gives the highest level A _m . 15. The method according to any one of claims 7 to 12, characterized in that a combination of frequency, charge and duration is selected that will give the highest level I _k .