Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M3/00—Conversion of DC power input into DC power output
  • H02M3/22—Conversion of DC power input into DC power output with intermediate conversion into AC
  • H02M3/24—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters
  • H02M3/28—Conversion of DC power input into DC power output with intermediate conversion into AC by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate AC
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
  • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
  • B03C3/34—Constructional details or accessories or operation thereof
  • B03C3/66—Applications of electricity supply techniques
  • B03C3/68—Control systems therefor
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
  • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
  • H02M7/02—Conversion of AC power input into DC power output without possibility of reversal
  • H02M7/04—Conversion of AC power input into DC power output without possibility of reversal by static converters
  • H02M7/06—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode
  • H02M7/10—Conversion of AC power input into DC power output without possibility of reversal by static converters using discharge tubes without control electrode or semiconductor devices without control electrode arranged for operation in series, e.g. for multiplication of voltage
  • H02M7/103—Containing passive elements (capacitively coupled) which are ordered in cascade on one source

Definitions

• the present invention relates to a generator and a method of generating high continuous voltage, and a dust collector using this generator.
• DC voltage generators with:
• a current switch adapted to receive a direct current input and to output a voltage and a polyphase current formed of N periodic currents out of phase with each other, the phase shifts of the N periodic currents being uniformly distributed between 0 and 2; ⁇ radians, where 2% radians corresponds to a period of the fundamental frequency f 0 of the periodic currents and N is an integer greater than or equal to three, the switch having N branches connected in parallel between input and output points of direct current, each branch being formed of an upper half-leg and a lower half-leg connected in series via a mid-point, each mid-point respectively delivering one of the phase-shifted periodic currents of the polyphase current , each upper or lower half-limb having a controllable switch adapted to switch between a passing state in the the current can pass through said half-branch and a non-conducting state in which no current can flow through said half-branch in one direction or the other,
• a transformer connected to the output of the switch, the transformer being able to transform the polyphase voltage into a high polyphase voltage of higher amplitude
• a rectifier connected to the secondary of the transformer, this rectifier being able to transform the high polyphase voltage by the transformer into a high rectified voltage, and a control unit of the switches of the switch.
• the switches of the current switch are bidirectional in current.
• Existing high voltage generators are working properly.
• the invention therefore aims to provide a high-voltage continuous generator whose electrical efficiency or the power density (W / kg) is improved.
• each switch comprises a controllable transistor connected in series with a diode so as to form a unidirectional current switch, the current being able to pass in the on state only from the terminal positive towards the negative terminal, and
• the steering unit is able to:. controlling the switching from the on state to the off state of a switch of an upper half-branch only at a time when a switch on another upper half-branch is in the on state, and
• the direct current received from a power source is never interrupted because a switch goes from the on state to the off state only if a parallel switch allows the DC current to continue to flow is.
• the fact of not interrupting the direct current avoids voltage peaks, and therefore the presence of current harmonics and filtering devices of these peaks. This ultimately reduces the overall size of the generator and improves its performance.
• the current source also makes it possible to overcome the imperfections of the transformer which has the role of charging capacitors through a diode.
• the presence of unidirectional current switches avoids that a short-circuit current flows in a primary bearing of the transformer when two switches of two upper half-branches, respectively lower, are simultaneously in the on state. Preventing such a short circuit from occurring limits the current harmonics and therefore increases the electrical efficiency of the generator.
• control unit is able to control the switching of each switch from the on state to the off state and from the non-on state to the on state once per period 1 / f 0 ;
• control unit is able to keep each switch in the on state at most during - + -;
• the fundamental frequency f 0 is greater than I kHz
• the rectifier comprises at least one voltage rectifier-booster stage, each stage comprising:
• N output points Sn each output point Sn being connected to the i-th phase of the high polyphase voltage without passing through a unidirectional current switch
• an output point S 2 connected to the neutral of the high polyphase voltage without passing through a unidirectional current switch, the output point being a DC voltage output point rectified and multiplied
• N capacitors Cn each capacitor Cn being connected between the entry point E 11 and the exit point Sn without passing through a unidirectional current switch
• N switches I 11 unidirectional current each read switches being connected between the output points S 2 and Su without passing through a capacitor, this switch read allowing only the current to flow from the output point S 2 to the output point Su in the case of a rectified voltage and multiplied negative or in the opposite direction in the case of a rectified voltage and positive multiplied
• a capacitor C 2 connected without passing through a unidirectional current switch between the entry point E 2 and the exit point S 2 ,.
• N switches 1 2i unidirectional current, each switch l 2i being connected without passing through a capacitor between the point of exit S 11 - and the point of entry E 2 , this switch l 2i allowing only the current of circulating capacitor Cn to capacitor C 2 in the case of a rectified voltage and multiplied negative or in the opposite direction in the case of a rectified voltage and positive multiplied;
• the rectifier comprises at least first and second rectifier-multiplier stages connected in series, that is to say that the output points Sy 1 and S 2 of the first stage are directly connected, respectively, to the entry points And E 2 of the second stage, and the generator comprises a continuous high-voltage selector adapted to connect the output point S 2 of the first stage to a high-voltage output terminal and, alternately, the output point S 2 from the second stage to the same high voltage DC output terminal;
• N is equal to three and in which the transformer with three primary windings connected in delta, each primary winding being connected to a respective phase of the polyphase current delivered by the current switch, and the transformer with three secondary windings connected in a star, each secondary windings delivering a respective phase of the high polyphase voltage;
• the time interval which separates the moment when a switch of an upper or lower branch goes from the non-on state to the on state and the moment when a switch of another upper branch, respectively lower, passing from the passing state to the off state is less than.
• selecting a operating frequency of the switch greater than 1 kHz decreases the size of the transformer and the generator
• the structure of the rectifier constructed from the unidirectional switches lu and fei and with the aid of the capacitors Cn and C 2 makes it possible to straighten and raise simultaneously and simply the voltage
• the invention also relates to a method of generating a high DC voltage using the above generator, this method comprising:
• the subject of the invention is also an electrostatic precipitator comprising:
• At least one electrode capable of ionizing dust present in a smoke this electrode being connected to the high voltage generator, and
• At least one plate capable of attracting the ionized dust this plate being connected to a reference potential.
• FIG. 1 is a schematic illustration of an electrostatic precipitator using a continuous high voltage generator
• FIG. 2 is an electronic block diagram of the continuous high voltage generator used in the dust collector of FIG. 1;
• FIG. 3 is a flowchart of a method of generating a continuous high voltage using the generator of the Figure 2, and
• FIGS. 4 to 6 are timing diagrams of switch control signals of the generator of FIG. 2.
• FIG. 1 shows an industrial installation 2 equipped with a chimney 4 projecting into the atmosphere of smoke 6 depleted of dust.
• This installation 2 also comprises a conduit 8 in which circulates smoke laden with dust. Between conduit 8 and the chimney 6 is interposed at least one chamber of an electrostatic precipitator 10.
• the dust collector 10 is able to remove a large part of the dust present in the smoke before it is evacuated via the chimney 4.
• a dust collector is formed of several enclosures traversed successively by the smoke to be dusted. These speakers are also known as "field". To simplify FIG. 1, only one enclosure 12 has been shown. This enclosure 12 is fluidly connected on one side to the duct 8 and on the other side to the chimney 4.
• the enclosure 12 comprises:
• an electrode 14 capable of ionizing the dust present in the smoke
• a plate 16 connected to a reference potential, for example here, to the ground, on which are deposited the ionized dust.
• the direction of circulation of the fumes inside the enclosure 12 is represented by an arrow F.
• the dust collector 10 also comprises a hammer 18 capable of striking a face of the plate 16 to remove the dust which has accumulated on the opposite face of the plate 16.
• a hopper 20 is disposed below and vertically of the plate 16 so as to collect the dust taken off as a result of the percussion of the plate 16 by the hammer 18.
• This hopper is designed to guide the dust off to a container such as, for example, the bucket of a truck 22.
• the electrode 14 is electrically connected to a negative high-voltage generator 24.
• high voltage is meant here a DC voltage whose amplitude in absolute value is greater than 10 kV.
• the absolute value of the high DC voltage generated is less than 500 kV.
• the generator 24 is connected via an information transmission network 26 to a supervisor 28 able to control the operation of the dust collector 10.
• Figure 2 shows in more detail the generator 24.
• the generator 24 is connected to a controllable source 34 of direct current.
• the source 34 is a three-phase rectifier followed by a chopper capable of generating a low-ripple continuous current ( ⁇ 30%) from a three-phase current delivered by an electricity distribution network.
• the electricity distribution network is a network distributing three-phase current at a voltage of between 300 and 400 Vac and at a frequency of between 50 and 60 Hz.
• the source is incorporated inside the same housing as that containing the generator 24.
• the direct current delivered by the source 34 is here indicated by an arrow I.
• the source 34 has a positive terminal 36 and a negative terminal 38.
• the generator 24 comprises successively: a current switch 40 capable of generating a current and a three-phase voltage,
• a transformer 42 able to generate a high three-phase voltage from the three-phase current generated by the switch 40
• a rectifier-multiplier 44 able both to rectify and to multiply the high three-phase voltage generated by the transformer 42 in order to produce a DC voltage that has been rectified and multiplied
• the switch 40 includes an entry point 50 and an exit point
• the switch 40 also comprises three switching branches 54 to 56 connected in parallel between the points 50 and 52.
• Each branch 54 to 56 comprises a midpoint, respectively, 60 to
• Midpoints 60 to 62 are respectively connected to ends 64 to 66 of primary winding 68 to 70 of transformer 42.
• the branches 54 to 56 are identical to each other with the exception that their respective mid-points 60 to 62 are connected to different primary windings of the transformer 42.
• the branch 54 consists of an upper half-branch connected between the point 60 and the point 50 and a lower half-branch connected between the point 60 and the point 52.
• the upper half-branch and the lower half-branch each comprise a controllable switch, respectively 74 and 76, unidirectional current.
• the switch 74 is made using a diode 78 connected in series with an IGBT transistor (Insulated Gate Bipolar Transistor) 80.
• IGBT transistor Insulated Gate Bipolar Transistor
• the anode of the diode 78 is connected to the point 50 while the cathode of the diode 78 is connected to the collector of the transistor 80.
• the emitter of the transistor 80 is connected to the mid-point 60.
• the switch 76 is, for example, produced by means of an IGBT transistor 82 connected in parallel.
• the collector of the transistor 82 is connected to the mid-point 60 and the emitter of this transistor is connected to the anode of the diode 84.
• the cathode of the diode 84 is connected to point 52.
• Capacitors 86 at 88 are connected in parallel between the terminals, respectively, of the primary windings 68 to 70.
• the capacitance of these capacitors 86 to 88 is chosen to attenuate the self-leakage effect and improve the EMC behavior (Electromagnetic Compatibility) of the transformer.
• the primary windings 68 to 70 of the transformer 42 are connected in a triangle.
• the primary windings are magnetically connected via a magnetic core 90 to three secondary windings 92 to 94 connected in a star.
• the ends of secondary windings 92 to 94 connected together are themselves connected to a neutral point 96, itself connected to ground 98.
• the winding ratio n between the secondary and primary windings is greater than ten so that the amplitude of the single voltage is at least a factor of ten.
• the ratio n is chosen greater than or equal to 27.
• the other ends of the secondary windings 92 to 94 are directly connected to respective inputs En, E 12 and E 13 of a first stage 102 of the rectifier-multiplier 44.
• the rectifier-multiplier 44 is formed of several stages connected in series. For example, here four stages 102 to 105 are shown. Each stage multiplies by a predetermined coefficient K the three-phase voltage present at its inputs.
• the stage 102 comprises the three entry points En, E 12 and E 13 as well as an entry point E2 connected to the neutral point 96 via a low value resistor R serving as a shunt for the measurement. of the current.
• the stage 102 also comprises four output points Sn, S 12 , S 13 and S 2 .
• the floor 102 includes:
• a capacitor C 2 directly connected on one side to the entry point E 2 and on the other side to the exit point S 2 and three diodes I 2 - I , I 22 and I 23 whose anodes are directly connected respectively to the outlet points Sn, S 12 and S 13 and whose cathodes are directly connected to the point of entry E 2 .
• the diodes I 11 , h 2 , li 3 , I 21 , 22 and 23 form unidirectional switches capable of passing current in one direction only.
• the orientation of the diodes in the stage 102 has been chosen to generate by the output S 2 a rectified voltage and negative multiplied.
• the following stages 103 to 105 are identical to the stage 102 and connected in series one after the other.
• serial connection here is meant the the input points En to Ei 3 and E 2 of the following stage are respectively connected to the output points S 1 - I to S 13 and S 2 of the previous stage.
• the output points S 2 of each of these stages are connected respectively to input points 110 to 113 of the selector 46.
• the selector 46 comprises a controllable switch 116 that can be switched between different positions in order to selectively connect one of the signal points. 110 to 113 to a DC high voltage output terminal 120.
• the output 120 is connected via a shock impedance 122 to a high voltage output 124 of the generator 24.
• the impedance of shocks 122 is formed of a resistor and an inductance configured to limit the current intensity in the event of a short circuit between the earth and the output 124.
• the output 124 is connected to the electrode 14.
• the generator 24 comprises a control unit 130.
• This unit 130 is able, in particular, to control the different controllable switches of the switch 40 and the selector 46.
• this unit 130 is able to drive the source 34 so as to control the amplitude of the direct current I and voltage.
• the unit 130 is connected via the network 26 to the supervisor 28 so that the operation of the generator 24 can be controlled remotely by the supervisor 28.
• the unit 130 adjusts the source 34 to adjust the amplitude of the direct current I. This also makes it possible to partially adjust the amplitude of the high DC voltage generated by the generator 24.
• the unit 130 controls the selector 46 to connect one of the input points 110 to 113 to the output point 120.
• This makes it possible to select the value of the high DC voltage delivered by the generator 24.
• the electrical power delivered by the generator 24 is independent of the position of the switch 116 in the selector 46.
• the selector 46 makes it possible to select a high DC voltage while delivering the same electrical power via the output 124.
• the unit 130 controls the switching of the switches of the branches 54 to 56 of the switch 40 in accordance with the timing diagrams shown in FIGS. 4 to 6.
• FIGS. 4 to 6 show the commutations of the switches, respectively, of the branches 54 to 56.
• the abscissa axis represents the time t.
• the ordinate axis represents the state of the switches. More precisely, when the signal is equal to "1", the switch of the upper half-branch is in the on state and the switch of the lower half-branch is in the off state. When the signal takes the value "0”, the switches of the upper and lower half branches are both in the off state. Finally, when the signal takes the value "-1", the switch of the upper half-branch is in the off state and the switch of the lower half-branch is in the on state.
• the switch control of the switch 40 is a full wave control, i.e. each switch is switched from the on state to the off state and state not passing to the passing state once per period.
• the unit 130 controls the switching of a switch from one upper half-branch of the on state to the non-on state only when a switch of another upper half-branch is already in the passing state so as not to interrupt the DC current.
• the unit 130 also applies the same strategy for the switches of the lower half-branches. Thus, the DC current generated by the source 34 is never interrupted.
• the time interval between switching from the non-on state to the on state of a switch of an upper half-branch precedes an interval At la switching from the on state to the off state of a switch of another upper half-branch.
• the interval At is chosen very small in front of the period 1 / f 0 of operation. Typically, the interval At is chosen lower than
• N is the number of phases of the
• the fundamental operating frequency of the switch 40 is between 1 kHz and 1 MHz.
• the frequency fo is chosen equal to the parallel resonance frequency of the transformer 42.
• the parallel resonance frequency is the frequency for which the vacuum impedance seen from a primary winding of the transformer is maximum. For this frequency, the transformer consumes its minimum of magnetizing current.
• the frequency f 0 is greater than 10 kHz and less than 100 kHz.
• the unidirectional switches of the switch are made from thyristors.
• the diode 78 may be upstream or downstream of the IGBT 80.
• the rectifier-multiplier 44 can be replaced by a simple rectifier devoid of capacity to multiply the DC voltage.
• the number of stages of the rectifier-multiplier connected in series can be arbitrary. However, preferably, it will be less than twelve.
• the generator 24 It is possible to adapt the generator 24 to produce a positive high DC voltage instead of a negative DC high voltage. For this, it suffices to replace the diodes I 11 , I 12 , I23, I 21 , I 22 and I 23 by identical diodes but connected in the opposite direction. Finally, the switch 40 can easily be adapted to generate a polyphase current having more than three phases. In this embodiment, the transformer 42 and the rectifier-multiplier 44 are adapted accordingly.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Automation & Control Theory (AREA)
• Rectifiers (AREA)
• Dc-Dc Converters (AREA)
• Electrostatic Separation (AREA)

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• 2007
  • 2007-01-08 FR FR0700074A patent/FR2911226B1/fr not_active Expired - Fee Related
• 2008
  • 2008-01-07 EP EP08761743A patent/EP2100363A2/de not_active Withdrawn
  • 2008-01-07 US US12/522,455 patent/US8331118B2/en not_active Expired - Fee Related
  • 2008-01-07 CN CN2008800018188A patent/CN101606310B/zh not_active Expired - Fee Related
  • 2008-01-07 WO PCT/FR2008/000019 patent/WO2008099087A2/fr not_active Ceased

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