Power supply device for electrostatic dust collection and power supply method for electrostatic dust collector

Abstract

The invention relates to a power supply device and a power supply method for electrostatic dust collection. The power supply device comprises an alternating current output circuit, a booster circuit and a first rectifying circuit, the current output circuit comprises a first alternating current output circuit and a second alternating current output circuit; the boost circuit comprises a first boost circuit and a second boost circuit. The output end of the first AC output circuit is connected with the input end of the first boost circuit. The output end of the second AC output circuit is connected with the input end of the second boost circuit. The first rectifier circuit comprises a first bridge rectifier circuit and a second bridge rectifier circuit. The power supply device can switch different power supply modes through the control system so as to better adapt to the change of the working condition of the electric dust remover. The narrow pulse voltage can be superposed through the direct-current voltage, the peak electric field intensity is improved, the voltage drop of a polar plate dust layer can be effectively reduced, the generation of back corona caused by high specific resistance is inhibited, and the dust removal efficiency is improved.

Description

Technical Field

[0001] The invention relates to a power supply device for electrostatic dust removal and a power supply method for an electrostatic dust remover, belonging to a power supply used for an electrostatic dust removal device. Background Art

[0002] The working principle of the electrostatic precipitator is to use a dust removal high-voltage DC power supply to power the electric field, so that the flue gas is ionized when passing through the electric field. The dust in the airflow is separated from the airflow under the action of the electric field. A large number of negatively charged particles move toward the dust collecting plate under the action of the electric field, and fall off after being captured in the electrode plate. The electrostatic precipitator is the leading technical equipment for the efficient treatment of flue gas dust in coal-fired power plants, metallurgy, building materials, chemical industry and other industries. As the core equipment of the electrostatic precipitator, the high-voltage power supply plays an extremely important supporting role in the industry's energy conservation and emission reduction.

[0003] At present, the DC power supply devices of electrostatic precipitators are mainly single-phase industrial frequency power supply, three-phase power supply, high-frequency power supply, etc. Single-phase industrial frequency power supply has been gradually phased out due to its disadvantages such as low power factor, low dust collection efficiency, and excessive ripple coefficient of power supply voltage waveform (the average value and peak value have a difference of 20%-30%). The power factor of three-phase power supply is relatively high, and its voltage waveform ripple coefficient is small (about 5%). However, due to the characteristics of the three-phase power supply circuit, the impact current is large during flashover, and the flashover control characteristics are poor. In order to avoid damage to the equipment, the operating parameters are usually set low. At the same time, the intermittent pulse power supply technology of the three-phase power supply cannot adapt to changes in working conditions, and the dust removal efficiency is low. High-frequency power supply is considered to be one of the most ideal dust removal power supplies at this stage. It has the characteristics of small output ripple when pure DC power supply and arbitrarily adjustable intermittent ratio when intermittent power supply. However, high-frequency power supply has problems such as high high-frequency heat generation and difficulty in capacity increase.

[0004] An electrostatic precipitator chamber generally has multiple electric fields. Taking the four electric fields as an example, the first electric field requires a large current to facilitate dust charging, and the fourth electric field requires a high voltage to enhance dust collection in the rear electric field due to the characteristics of flue gas dust (small dust radius). The existing power supply is limited by the limitations of its topology and power design. It is insufficient in the large current capacity of the first electric field. At the same time, when the fourth electric field is processing conditions containing fine dust particles, it cannot provide high voltage, affecting the dust removal efficiency.

[0005] During operation, the electrostatic precipitator is highly sensitive to differences in coal type, ash characteristics, and flue gas conditions. Domestic coal-fired boilers use a wide variety of complex coal types and variable operating conditions, while the existing power supply mode is single, which makes it difficult for them to fully adapt to the changing needs of the electrostatic precipitator under complex working conditions.

[0006] The Chinese invention patent with application number CN201910113254.7 discloses a 220kV ultra-high voltage electrostatic precipitator power supply, which obtains 220kV twelve-pulse ultra-high voltage direct current through a six-phase twelve-pulse rectifier transformer and a three-phase rectifier bridge in series. However, the power supply cannot change the power supply mode according to the electrostatic precipitator environment and cannot cope with complex electrostatic precipitator scenarios. Summary of the invention

[0007] In order to overcome the above problems, the present disclosure provides a power supply device for electrostatic precipitator and a power supply method for electrostatic precipitator.

[0008] First aspect

[0009] A power supply device for electrostatic dust removal, comprising: an AC output circuit, a boost circuit and a first rectifier circuit;

[0010] The current output circuit includes a first AC output circuit and a second AC output circuit;

[0011] The boost circuit comprises a first boost circuit and a second boost circuit;

[0012] The output end of the first AC output circuit is connected to the input end of the first boost circuit, and the output end of the second AC output circuit is connected to the input end of the second boost circuit;

[0013] The first rectifier circuit includes a first bridge rectifier circuit and a second bridge rectifier circuit;

[0014] The first output terminal and the second output terminal of the first boost circuit are connected to the first port and the third port of the first bridge rectifier circuit, the second port of the first bridge rectifier circuit can be grounded or connected to the first contact, and the fourth port of the first bridge rectifier circuit is connected to the input terminal of the electrostatic precipitator;

[0015] The first output terminal and the second output terminal of the second boost circuit are connected to the first port and the third port of the second bridge rectifier circuit, the second port of the second bridge rectifier circuit is grounded, and the fourth port of the second bridge rectifier circuit can be selectively connected to the input terminal of the electrostatic precipitator or to the first contact;

[0016] At least one embodiment of the present disclosure provides a power supply device for electrostatic precipitator, further comprising a second rectifier circuit, the second rectifier circuit being connected to an AC power source to rectify the AC power into a DC power;

[0017] The first AC output circuit and the second AC output circuit are full-bridge inverter circuits;

[0018] The first AC output circuit and the second AC output circuit convert the DC power output by the second rectifier circuit into AC power for output.

[0019] In a power supply device for electrostatic precipitator provided by at least one embodiment of the present disclosure, the first AC output circuit includes a first IGBT, a second IGBT, a third IGBT and a fourth IGBT;

[0020] The collector of the first IGBT is connected to the positive electrode of direct current, and the emitter of the first IGBT is connected to the collector of the third IGBT;

[0021] The collector of the second IGBT is connected to the positive electrode of direct current, and the emitter of the second IGBT is connected to the collector of the fourth IGBT;

[0022] The emitters of the third IGBT and the fourth IGBT are both connected to the negative electrode of the direct current;

[0023] The bases of the first IGBT, the second IGBT, the third IGBT and the fourth IGBT are all connected to the control unit;

[0024] The second AC output circuit includes a fifth IGBT, a sixth IGBT, a seventh IGBT and an eighth IGBT;

[0025] The collector of the fifth IGBT is connected to the positive electrode of the direct current, and the emitter of the fifth IGBT is connected to the collector of the seventh IGBT;

[0026] The collector of the sixth IGBT is connected to the positive electrode of the direct current, and the emitter of the sixth IGBT is connected to the collector of the eighth IGBT;

[0027] The emitters of the seventh IGBT and the eighth IGBT are both connected to the negative electrode of the direct current;

[0028] Bases of the fifth IGBT, the sixth IGBT, the seventh IGBT and the eighth IGBT are all connected to a control unit.

[0029] In a power supply device for electrostatic precipitator provided in at least one embodiment of the present disclosure, the alternating current input into the second rectifier circuit is three-phase power.

[0030] In a power supply device for electrostatic precipitator provided by at least one embodiment of the present disclosure, the second rectifier circuit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode and a sixth diode;

[0031] The anode of the first diode is connected to the cathode of the second diode and the first phase of the three-phase electricity;

[0032] The anode of the third diode is connected to the cathode of the fourth diode and the second phase of the three-phase electricity;

[0033] The anode of the fifth diode is connected to the cathode of the sixth diode and the third phase of the three-phase electricity.

[0034] In a power supply device for electrostatic precipitator provided in at least one embodiment of the present disclosure, a filter circuit is provided between the second rectifier circuit and the AC output circuit.

[0035] In a power supply device for electrostatic precipitator provided by at least one embodiment of the present disclosure, the filter circuit includes a coil and a capacitor C1, one end of the capacitor C1 is connected to the positive output end of the second rectifier circuit through the coil, and the other end is connected to the negative output end of the second rectifier circuit.

[0036] Second aspect

[0037] A method for powering an electrostatic precipitator, wherein the electrostatic precipitator of the present disclosure uses the electrostatic precipitator power supply device of the first aspect to power the electrostatic precipitator, including powering the electrostatic precipitator with a DC voltage in parallel or a DC voltage in series;

[0038] When the DC voltage is connected in parallel to supply power, the second port of the first bridge rectifier circuit is grounded, and the fourth port of the second bridge rectifier circuit is connected to the input end of the electrostatic precipitator; the control unit applies the same first control signal to the first IGBT to the eighth IGBT to control the first IGBT to the eighth IGBT to be periodically disconnected and turned on, and the disconnection and conduction time are the same;

[0039] When power is supplied in series via a DC voltage, the second port of the first bridge rectifier circuit is connected to the first contact, and the fourth port of the second bridge rectifier circuit is connected to the first contact; the control unit applies the same first control signal to each IGBT of the first AC output circuit and the second AC output circuit to control each IGBT to be periodically disconnected and turned on, and the disconnection and conduction times are the same.

[0040] The electrostatic precipitator power supply method provided in at least one embodiment of the present disclosure further includes powering the electrostatic precipitator by superimposing a direct current voltage with a narrow pulse voltage;

[0041] When power is supplied by superimposing a DC voltage with a narrow pulse voltage, the second port of the first bridge rectifier circuit is connected to the first contact, and the fourth port of the second bridge rectifier circuit is connected to the first contact; the control unit applies a second control signal to the first AC output circuit to control the periodic disconnection and conduction of each IGBT of the first AC output circuit;

[0042] The control unit periodically applies a third control signal to the second AC output circuit, the third control signal includes a conduction area and a disconnection area, the conduction area controls the periodic disconnection and conduction of each IGBT of the second AC output circuit, and the period, on-time and disconnection time are the same as the second control signal, and the disconnection area controls the disconnection of each IGBT of the second AC output circuit.

[0043] The third aspect

[0044] An intelligent control method for a power supply device for electrostatic precipitator, controlling the power supply device for electrostatic precipitator according to the power supply method for electrostatic precipitator according to the second aspect, controlling the switching frequency of the IGBT and switching different power supply modes according to the operating conditions of the electrostatic precipitator:

[0045] Calculate the electrostatic dust collection efficiency η:

[0046]

[0047] Among them, e is a constant, A is the dust collecting plate area, Q is the flue gas volume, and ω is the dust driving speed, specifically:

[0048] ω=β·V p ·V m ;

[0049] Among them, β is a constant, Vp is the secondary voltage peak value, and Vm is the secondary voltage average value;

[0050] During the voltage boosting stage of the electrostatic precipitator, the power supply device for electrostatic precipitator uses parallel power supply to boost the voltage and judge whether the electric field flashes over; when the electric field flashes over, the power supply device for electrostatic precipitator is controlled to operate at a voltage lower than the flashover point; when the secondary voltage reaches 72KV and no flashover occurs, the power supply device for electrostatic precipitator continues to boost the voltage to the flashover point voltage by using series power supply;

[0051] When the electrostatic precipitator is in the stable stage and the equipment is in the series power supply mode, the DC power supply mode and the pulse power supply mode are adopted respectively, and the switching frequency of each IGBT is adjusted to obtain different secondary voltage amplitudes, and the ratio of the conduction area and the disconnection area of ​​the pulse power supply is adjusted to obtain different pulse voltage peaks. By comparing the different switching frequencies and the ratio of the conduction area and the disconnection area under the DC power supply mode and the pulse power supply mode, the situation with the maximum dust driving speed ω is obtained as the optimal operating parameter;

[0052] When the electrostatic precipitator has back corona phenomenon, switch to pulse power supply mode and adjust the operating parameters until the back corona phenomenon disappears;

[0053] When the electrostatic precipitator frequently flashes over or shorts out, it switches to parallel power supply mode to shunt the flashover current or short-circuit current.

[0054] The present invention has the following beneficial effects:

[0055] The power supply device disclosed in the present invention can switch different power supply modes through the control system to better adapt to the changes in the working conditions of the electrostatic precipitator. It has a high-power resonant circuit and can output a DC voltage with a large current and high voltage, effectively increasing the charge amount and charging efficiency of fine dust, thereby significantly improving the capture efficiency of PM2.5 fine particles. By superimposing a narrow pulse voltage on a DC voltage, the peak electric field strength is increased, which can effectively reduce the voltage drop of the dust layer on the electrode plate, inhibit the generation of back corona caused by high specific resistance, and improve the dust removal efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 FIG. 4 is a circuit diagram of a power supply device according to an embodiment of the present invention.

[0057] Figure 2 This is a DC voltage parallel power supply circuit diagram of an embodiment of the present invention.

[0058] Figure 3 This is a DC voltage series power supply circuit diagram of an embodiment of the present invention.

[0059] Figure 4 Schematic diagram of the voltage output waveform in the DC power supply mode of the embodiment of the present invention.

[0060] Figure 5 This is a voltage output model in the pulse power supply mode of an embodiment of the present invention. DETAILED DESCRIPTION

[0061] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0062] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0063] refer to Figure 1 , one aspect of the present disclosure provides a power supply device for electrostatic precipitator, comprising: an AC output circuit, a boost circuit and a first rectifier circuit;

[0064] The current output circuit includes a first AC output circuit and a second AC output circuit;

[0065] The boost circuit comprises a first boost circuit and a second boost circuit;

[0066] The output end of the first AC output circuit is connected to the input end of the first boost circuit, and the output end of the second AC output circuit is connected to the input end of the second boost circuit;

[0067] The first rectifier circuit includes a first bridge rectifier circuit and a second bridge rectifier circuit;

[0068] The first output terminal and the second output terminal of the first boost circuit are connected to the first port and the third port of the first bridge rectifier circuit, the second port of the first bridge rectifier circuit can be grounded or connected to the first contact, and the fourth port of the first bridge rectifier circuit is connected to the input terminal of the electrostatic precipitator;

[0069] The first output terminal and the second output terminal of the second boost circuit are connected to the first port and the third port of the second bridge rectifier circuit, the second port of the second bridge rectifier circuit is grounded, and the fourth port of the second bridge rectifier circuit can be selectively connected to the input terminal of the electrostatic precipitator or to the first contact;

[0070] refer to Figure 1, switches S1 and S2 are on-load voltage-adjusting switching switches, which have the connection mode of switching the first bridge rectifier circuit and the second bridge rectifier circuit under load. At the same time, switch S1 and switch S2 are interlocked and can only be at point 1 or point 2 at the same time. The two points corresponding to switch S1 and switch S2 are the first contact points.

[0071] refer to Figure 1 The first bridge rectifier circuit and the second bridge rectifier circuit respectively include four diodes.

[0072] Among them, the cathode of the upper right diode is connected to the anode of the upper left diode, and the anode is connected to the anode of the lower right diode; the cathode of the lower left diode is connected to the cathode of the upper left diode, and the anode is connected to the cathode of the lower right diode.

[0073] In this connection mode, the cathode and anode of the upper right diode are respectively the first port and the fourth port of the bridge rectifier circuit, and the cathode and anode of the lower left diode are respectively the second port and the third port of the bridge rectifier circuit.

[0074] refer to Figure 1 There are two groups of resonant circuits composed of resonant capacitors, transformers and electrostatic precipitator loads, one group is C2 and T1, and the other group is C3 and T2. This can greatly increase the current peak that the circuit can withstand, effectively reduce the pressure on the key switching element IGBT, and greatly improve the reliability of the circuit.

[0075] At least one embodiment of the present disclosure provides a power supply device for electrostatic precipitator, further comprising a second rectifier circuit, the second rectifier circuit being connected to an AC power source to rectify the AC power into a DC power;

[0076] The first AC output circuit and the second AC output circuit are full-bridge inverter circuits;

[0077] The first AC output circuit and the second AC output circuit convert the DC power output by the second rectifier circuit into AC power for output.

[0078] The output of narrow pulse voltage can be achieved by outputting different AC currents through the first AC output circuit and the second AC output circuit.

[0079] In a power supply device for electrostatic precipitator provided by at least one embodiment of the present disclosure, the first AC output circuit includes a first IGBT, a second IGBT, a third IGBT and a fourth IGBT;

[0080] The collector of the first IGBT is connected to the positive electrode of direct current, and the emitter of the first IGBT is connected to the collector of the third IGBT;

[0081] The collector of the second IGBT is connected to the positive electrode of direct current, and the emitter of the second IGBT is connected to the collector of the fourth IGBT;

[0082] The emitters of the third IGBT and the fourth IGBT are both connected to the negative electrode of the direct current;

[0083] Bases of the first IGBT, the second IGBT, the third IGBT and the fourth IGBT are all connected to a control unit.

[0084] In a power supply device for electrostatic precipitator provided by at least one embodiment of the present disclosure, the second AC output circuit includes a fifth IGBT, a sixth IGBT, a seventh IGBT and an eighth IGBT;

[0085] The collector of the fifth IGBT is connected to the positive electrode of the direct current, and the emitter of the fifth IGBT is connected to the collector of the seventh IGBT;

[0086] The collector of the sixth IGBT is connected to the positive electrode of the direct current, and the emitter of the sixth IGBT is connected to the collector of the eighth IGBT;

[0087] The emitters of the seventh IGBT and the eighth IGBT are both connected to the negative electrode of the direct current;

[0088] Bases of the fifth IGBT, the sixth IGBT, the seventh IGBT and the eighth IGBT are all connected to a control unit.

[0089] Each IGBT is an n-channel fast recovery type (FRD) IGBT, which can meet high-frequency switching.

[0090] In a power supply device for electrostatic precipitator provided in at least one embodiment of the present disclosure, the alternating current input into the second rectifier circuit is three-phase power.

[0091] In a power supply device for electrostatic precipitator provided by at least one embodiment of the present disclosure, the second rectifier circuit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode and a sixth diode;

[0092] The anode of the first diode is connected to the cathode of the second diode and the first phase of the three-phase electricity;

[0093] The anode of the third diode is connected to the cathode of the fourth diode and the second phase of the three-phase electricity;

[0094] The anode of the fifth diode is connected to the cathode of the sixth diode and the third phase of the three-phase electricity.

[0095] In a power supply device for electrostatic precipitator provided in at least one embodiment of the present disclosure, a filter circuit is provided between the second rectifier circuit and the AC output circuit.

[0096] In a power supply device for electrostatic precipitator provided by at least one embodiment of the present disclosure, the filter circuit includes a coil and a capacitor C1, one end of the capacitor C1 is connected to the positive output end of the second rectifier circuit through the coil, and the other end is connected to the negative output end of the second rectifier circuit.

[0097] refer to Figure 1-4 , another aspect of the present disclosure provides a method for powering an electrostatic precipitator, wherein the electrostatic precipitator power supply device of the present disclosure powers the electrostatic precipitator, including powering the electrostatic precipitator with a DC voltage in parallel or a DC voltage in series;

[0098] refer to Figure 2 and 4 , when the DC voltage is used for parallel power supply, the second port of the first bridge rectifier circuit is grounded, and the fourth port of the second bridge rectifier circuit is connected to the input end of the electrostatic precipitator; the control unit applies the same first control signal to the first IGBT to the eighth IGBT to control the first IGBT to be periodically disconnected and turned on, and the disconnection and conduction time are the same.

[0099] At this time, the first boost circuit and the second boost circuit generate DC voltage respectively and are connected in parallel to the electrostatic precipitator ESP, which can provide a DC waveform with a secondary voltage of 72KV and a secondary current of 3A or above, greatly improving the load current of the electrostatic precipitator and increasing the amount of dust collected.

[0100] refer to Figure 3 and 4 , when the power is supplied in series by a DC voltage, the second port of the first bridge rectifier circuit is connected to the first contact, and the fourth port of the second bridge rectifier circuit is connected to the first contact; the control unit applies the same first control signal to each IGBT of the first AC output circuit and the second AC output circuit to control each IGBT to be periodically disconnected and turned on, and the disconnection and conduction time are the same.

[0101] At this time, the first boost circuit and the second boost circuit respectively generate DC voltages and are connected in series to the electrostatic precipitator ESP, which can provide DC pulse high voltage of more than 100KV, effectively improving the charge amount and charging efficiency of the dust.

[0102] refer to Figure 3 and 5 , the electrostatic precipitator power supply method provided in at least one embodiment of the present disclosure further includes powering the electrostatic precipitator by superimposing a DC voltage with a narrow pulse voltage;

[0103] When power is supplied by superimposing a DC voltage with a narrow pulse voltage, the second port of the first bridge rectifier circuit is connected to the first contact, and the fourth port of the second bridge rectifier circuit is connected to the first contact; the control unit applies a second control signal to the first AC output circuit to control the periodic disconnection and conduction of each IGBT of the first AC output circuit;

[0104] The control unit periodically applies a third control signal to the second AC output circuit, the third control signal includes a conduction area and a disconnection area, the conduction area controls the periodic disconnection and conduction of each IGBT of the second AC output circuit, and the period, on-time and disconnection time are the same as the second control signal, and the disconnection area controls the disconnection of each IGBT of the second AC output circuit.

[0105] At this time, the DC voltage generated by the first boost circuit and the narrow pulse voltage generated by the second boost circuit are connected in parallel to the electrostatic precipitator ESP, which can provide a pulse peak voltage of more than 200KV, inhibit the generation of back corona, and greatly improve the collection rate of high resistivity dust.

[0106] The third aspect

[0107] An intelligent control method for a power supply device for electrostatic precipitator, controlling the power supply device for electrostatic precipitator according to the power supply method for electrostatic precipitator according to the second aspect, controlling the switching frequency of the IGBT and switching different power supply modes according to the operating conditions of the electrostatic precipitator:

[0108] Calculate the electrostatic dust collection efficiency η:

[0109]

[0110] Among them, e is a constant, A is the dust collecting plate area, Q is the flue gas volume, and ω is the dust driving speed, specifically:

[0111] ω=β·V p ·V m ;

[0112] Among them, β is a constant, Vp is the secondary voltage peak value, and Vm is the secondary voltage average value;

[0113] During the voltage boosting stage of the electrostatic precipitator, the power supply device for electrostatic precipitator uses parallel power supply to boost the voltage and judge whether the electric field flashes over; when the electric field flashes over, the power supply device for electrostatic precipitator is controlled to operate at a voltage lower than the flashover point; when the secondary voltage reaches 72KV and no flashover occurs, the power supply device for electrostatic precipitator continues to boost the voltage to the flashover point voltage by using series power supply;

[0114] When the electrostatic precipitator is in the stable stage and the equipment is in the series power supply mode, the DC power supply mode and the pulse power supply mode are adopted respectively, and the switching frequency of each IGBT is adjusted to obtain different secondary voltage amplitudes, and the ratio of the conduction area and the disconnection area of ​​the pulse power supply is adjusted to obtain different pulse voltage peaks. By comparing the different switching frequencies and the ratio of the conduction area and the disconnection area under the DC power supply mode and the pulse power supply mode, the situation with the maximum dust driving speed ω is obtained as the optimal operating parameter;

[0115] When the electrostatic precipitator has back corona phenomenon, switch to pulse power supply mode and adjust the operating parameters until the back corona phenomenon disappears;

[0116] When the electrostatic precipitator frequently flashes over or shorts out, it switches to parallel power supply mode to shunt the flashover current or short-circuit current.

[0117] The method increases the operating voltage, suppresses the generation of back corona, and improves the dust removal efficiency of the electrostatic precipitator by controlling the switching frequency of the IGBT and switching different power supply modes according to the operating conditions of the electrostatic precipitator (boosting stage, stable stage, whether flashover occurs, whether back corona occurs, etc.).

[0118] When back corona occurs, the pulse power supply mode is automatically switched, and the inflection point of back corona is calculated according to the volt-ampere curve to find the most suitable operating parameters to suppress the back corona phenomenon. It has good energy-saving characteristics.

[0119] When the electrostatic precipitator frequently flashes over or shorts out due to changes in operating conditions, the equipment automatically switches to parallel power supply mode to shunt the flashover current or short-circuit current, reduce the impact on the transformer and electronic devices, and improve equipment stability.

[0120] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure made using the contents of the present invention's specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A power supply device for electrostatic precipitator, characterized in that: include: AC output circuit, boost circuit and first rectifier circuit; The current output circuit includes a first AC output circuit and a second AC output circuit; The boost circuit comprises a first boost circuit and a second boost circuit; The output end of the first AC output circuit is connected to the input end of the first boost circuit, and the output end of the second AC output circuit is connected to the input end of the second boost circuit; The first rectifier circuit includes a first bridge rectifier circuit and a second bridge rectifier circuit; The first output terminal and the second output terminal of the first boost circuit are connected to the first port and the third port of the first bridge rectifier circuit, the second port of the first bridge rectifier circuit can be grounded or connected to the first contact, and the fourth port of the first bridge rectifier circuit is connected to the input terminal of the electrostatic precipitator; The first output terminal and the second output terminal of the second boost circuit are connected to the first port and the third port of the second bridge rectifier circuit, the second port of the second bridge rectifier circuit is grounded, and the fourth port of the second bridge rectifier circuit can be selectively connected to the input terminal of the electrostatic precipitator or to the first contact.

2. The power supply device for electrostatic precipitator according to claim 1, characterized in that: It also includes a second rectifier circuit, which is connected to an AC power source and rectifies the AC power into a DC power; The first AC output circuit and the second AC output circuit are full-bridge inverter circuits; The first AC output circuit and the second AC output circuit convert the DC power output by the second rectifier circuit into AC power for output.

3. The power supply device for electrostatic precipitator according to claim 1 or 2, characterized in that: The first AC output circuit includes a first IGBT, a second IGBT, a third IGBT and a fourth IGBT; The collector of the first IGBT is connected to the positive electrode of direct current, and the emitter of the first IGBT is connected to the collector of the third IGBT; The collector of the second IGBT is connected to the positive electrode of direct current, and the emitter of the second IGBT is connected to the collector of the fourth IGBT; The emitters of the third IGBT and the fourth IGBT are both connected to the negative electrode of the direct current; The bases of the first IGBT, the second IGBT, the third IGBT and the fourth IGBT are all connected to the control unit; The second AC output circuit includes a fifth IGBT, a sixth IGBT, a seventh IGBT and an eighth IGBT; The collector of the fifth IGBT is connected to the positive electrode of the direct current, and the emitter of the fifth IGBT is connected to the collector of the seventh IGBT; The collector of the sixth IGBT is connected to the positive electrode of the direct current, and the emitter of the sixth IGBT is connected to the collector of the eighth IGBT; The emitters of the seventh IGBT and the eighth IGBT are both connected to the negative electrode of the direct current; Bases of the fifth IGBT, the sixth IGBT, the seventh IGBT and the eighth IGBT are all connected to a control unit.

4. The power supply device for electrostatic precipitator according to claim 2, characterized in that: The alternating current input to the second rectifying circuit is three-phase electricity.

5. The power supply device for electrostatic precipitator according to claim 4, characterized in that: The second rectifier circuit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode and a sixth diode; The anode of the first diode is connected to the cathode of the second diode and the first phase of the three-phase electricity; The anode of the third diode is connected to the cathode of the fourth diode and the second phase of the three-phase electricity; The anode of the fifth diode is connected to the cathode of the sixth diode and the third phase of the three-phase electricity.

6. The power supply device for electrostatic precipitator according to claim 2, characterized in that: A filter circuit is provided between the second rectifier circuit and the AC output circuit.

7. The power supply device for electrostatic precipitator according to claim 6, characterized in that: The filter circuit includes a coil and a capacitor C1. One end of the capacitor C1 is connected to the positive output end of the second rectifier circuit through the coil, and the other end of the capacitor C1 is connected to the negative output end of the second rectifier circuit.

8. A method for powering an electrostatic precipitator, wherein the electrostatic precipitator is powered by the electrostatic precipitator power supply device according to claim 3, characterized in that: It includes supplying power to the electrostatic precipitator with a DC voltage parallel supply or a DC voltage series supply; When the DC voltage is connected in parallel to supply power, the second port of the first bridge rectifier circuit is grounded, and the fourth port of the second bridge rectifier circuit is connected to the input end of the electrostatic precipitator; the control unit applies the same first control signal to the first IGBT to the eighth IGBT to control the first IGBT to the eighth IGBT to be periodically disconnected and turned on, and the disconnection and conduction time are the same; When power is supplied in series via a DC voltage, the second port of the first bridge rectifier circuit is connected to the first contact, and the fourth port of the second bridge rectifier circuit is connected to the first contact; the control unit applies the same first control signal to each IGBT of the first AC output circuit and the second AC output circuit to control each IGBT to be periodically disconnected and turned on, and the disconnection and conduction times are the same.

9. The electrostatic precipitator power supply method according to claim 8, characterized in that: It also includes supplying power to the electrostatic precipitator by superimposing a direct current voltage with a narrow pulse voltage; When the DC voltage is superimposed on the pulse voltage for power supply, the second port of the first bridge rectifier circuit is connected to the first contact, and the fourth port of the second bridge rectifier circuit is connected to the first contact; the control unit applies a second control signal to the first AC output circuit to control the periodic disconnection and conduction of each IGBT of the first AC output circuit; The control unit periodically applies a third control signal to the second AC output circuit, the third control signal includes a conduction area and a disconnection area, the conduction area controls the periodic disconnection and conduction of each IGBT of the second AC output circuit, and the period, on-time and disconnection time are the same as the second control signal, and the disconnection area controls the disconnection of each IGBT of the second AC output circuit.

10. An intelligent control method for a power supply device for electrostatic precipitator, wherein the power supply device for electrostatic precipitator is controlled according to the power supply method for electrostatic precipitator according to claim 9, characterized in that: Control the switching frequency of the IGBT and switch different power supply modes according to the operating conditions of the electrostatic precipitator: Calculate the electrostatic dust collection efficiency η: Among them, e is a constant, A is the dust collecting plate area, Q is the flue gas volume, and ω is the dust driving speed, specifically: ω=β·V p ·V m ; Among them, β is a constant, Vp is the secondary voltage peak value, and Vm is the secondary voltage average value; During the voltage boosting stage of the electrostatic precipitator, the power supply device for electrostatic precipitator uses parallel power supply to boost the voltage and judge whether the electric field flashes over; when the electric field flashes over, the power supply device for electrostatic precipitator is controlled to operate at a voltage lower than the flashover point; when the secondary voltage reaches 72KV and no flashover occurs, the power supply device for electrostatic precipitator continues to boost the voltage to the flashover point voltage by using series power supply; When the electrostatic precipitator is in the stable stage and the equipment is in the series power supply mode, the DC power supply mode and the pulse power supply mode are adopted respectively, and the switching frequency of each IGBT is adjusted to obtain different secondary voltage amplitudes, and the ratio of the conduction area and the disconnection area of ​​the pulse power supply is adjusted to obtain different pulse voltage peaks. By comparing the different switching frequencies and the ratio of the conduction area and the disconnection area under the DC power supply mode and the pulse power supply mode, the situation with the maximum dust driving speed ω is obtained as the optimal operating parameter; When the electrostatic precipitator has back corona phenomenon, switch to pulse power supply mode and adjust the operating parameters until the back corona phenomenon disappears; When the electrostatic precipitator frequently flashes over or shorts out, it switches to parallel power supply mode to shunt the flashover current or short-circuit current.

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