A control method for bipolar dual-reaction zone pulse air purification

Abstract

A control method for bipolar dual-reaction zone pulse air purification comprises an adjustable direct current voltage source, a filtering energy storage capacitor, a semiconductor H-bridge pulse generating circuit, a pulse boosting circuit, a positive pulse output high-voltage diode module, a negative pulse output high-voltage diode module and a control system. A bipolar pulse high-voltage power supply and a reactor with dual reaction zones are adopted. The positive pulse reaction zone uses positive pulses, and the negative pulse reaction zone uses negative pulses to treat gaseous pollutants. The method can maximize the treatment efficiency, reduce the generation of secondary pollutants, and reduce the impact of noise and vibration on the environment. A unified control system is adopted to simultaneously control the parameters of positive pulses and negative pulses, thereby simplifying the complexity of the control system, reducing maintenance costs, facilitating expansion to large-scale application scenarios, and effectively treating various gaseous pollutants.

Description

Technical Field

[0001] The invention relates to the fields of air conditioning and air purification, and in particular to a control method for bipolar and bi-reaction zone pulse air purification. Background Art

[0002] Pulse high-voltage discharge technology is suitable for the treatment of a variety of polluted gases, including volatile organic compounds (VOCs), sulfides, nitrides, odorous gases, sterilization, etc. It mainly uses a high-voltage pulse electric field to ionize gas molecules to form plasma. Under the action of the high-voltage pulse electric field, the gas molecules are accelerated and collide with each other, resulting in the occurrence of ionization. The positive ions and free electrons generated by ionization move at high speed in the electric field and are used to catalyze the degradation of pollutants in the gas. No additional harmful substances are produced during the technical treatment process, avoiding the problem of secondary pollution. The composition of volatile organic compounds (VOCs) is complex, including hydrocarbons, halogenated hydrocarbons, alcohols, ethers, ketones, esters, phenols, amines, nitriles and organic acids. Odor gases have complex components. They are usually a mixture of multiple chemical substances. These chemicals will release unpleasant odors under certain conditions. For example, industrial production, chemicals, pesticides, fertilizers, leather, oil refining and other industrial production processes will produce a large amount of odorous gases. Municipal treatment, urban sewage treatment, kitchen waste treatment, waste incineration plants and other municipal treatment facilities are also important sources of odorous gases. The complex composition of polluted gases brings challenges to polluted gas environmental protection equipment.

[0003] Pulse high-voltage discharge includes positive polarity pulse high-voltage discharge, negative polarity pulse high-voltage discharge, and AC pulse high-voltage discharge. Positive high-voltage pulse discharge refers to the discharge electrode of the reactor being connected to a positive high-voltage pulse, and the other electrode of the reactor being grounded. At this time, ionization occurs at the tip of the discharge electrode, and electrons and negative ions flow directly into the discharge electrode near the discharge electrode. The positive ions generated by the discharge electrode flow from the discharge electrode to the ground, forming a positive ion zone in most of the reactor space. Negative high-voltage pulse discharge refers to the discharge electrode of the reactor being connected to a negative high-voltage pulse, and the other electrode of the reactor being grounded. At this time, ionization occurs at the tip of the discharge electrode, and positive ions flow directly into the discharge electrode near the discharge electrode. The negative ions and electrons generated by the discharge electrode flow from the discharge electrode to the ground, forming a negative ion zone in most of the reactor space. AC high-voltage pulse discharge refers to the discharge electrode of the reactor being connected to an AC high-voltage pulse, and the other electrode of the reactor being grounded, and ionization is generated alternately by periodic changes. The positive ion zone and the negative ion zone have different removal effects and efficiencies for pollutants of different components in the polluted gas.

[0004] The existing technical solutions for using pulse high voltage technology to treat air pollution and purify the air are as follows:

[0005] Chinese invention patent CN114877460A discloses an air purification device for a medical ventilation system, which discloses an ionization module (100) and a micro-electrostatic module (200) mounted on the air outlet of the ionization module (100), characterized in that the ionization module (100) comprises: two insulating mounting parts (1) arranged opposite to each other; a plurality of negative plates (2) connected between the two insulating mounting parts (1), wherein the plurality of negative plates (2) are arranged at intervals up and down, and the spacing between two adjacent negative plates (2) is equal; and a plurality of positive pole axes (3) connected between the two insulating mounting parts (1), wherein each positive pole axis (3) is respectively arranged between two adjacent negative plates (2), and the spacing between the positive pole axis (3) and the two adjacent negative plates (2) is equal; when the positive pole axis (3) is connected to a high-voltage pulse current, a uniform electric field is formed between the positive pole axis (3) and the two adjacent negative plates (2).

[0006] Chinese invention patent CN112728707A discloses a miniature plasma dynamic air purifier, which includes a fan, a plasma generator, an electronic air filter, and a control circuit; the fan introduces external air into the purifier to form an airway, and the gas is purified through the electronic air filter and the plasma generator and generates a large amount of plasma. The control circuit includes at least two control units, each of which generates a DC high voltage of more than 6000V to supply the electronic air filter and the plasma generator respectively, and can control the fan and the plasma generator pulse control signal according to the external air quality to better purify the air. The purifier of the present invention can effectively purify the air and disinfect viruses; the entire device has a compact structure, can be miniaturized and lightweight, and is conducive to large-scale production and application.

[0007] The pulsed high-voltage power supply gas pollution treatment device as described above adopts a single polarity output high-voltage power supply, one point grounding, and positive or negative single polarity output to supply power to a reaction zone. The pulsed high voltage of AC output is also one point grounded, single point alternating output, and supplies power to the same reaction zone. There are huge differences in the positive pulse and negative pulse high-voltage discharge volt-ampere curves of the same reactor. When AC pulsed high-voltage discharge supplies power to the same reaction zone, the breakdown strength is low when the polarity is positive, and the plasma generated is weak when the polarity is negative, and the effect is not good; there is no method for the accurate calculation of the pulse short-circuit current, so as to provide a basis for the reasonable selection of the specifications of the pulse circuit short-circuit protection components. Summary of the invention

[0008] In view of the problems described in the background technology, the present invention proposes a control method for bipolar dual-reaction zone pulse air purification. The positive pulse high voltage and negative high voltage two independent pulse outputs of the high voltage power supply correspond to the independent positive plasma zone and negative plasma zone inside the reactor, respectively, forming positive and negative ion dual purification of polluted gas, unified control, and improving the purification effect of polluted gas containing complex components. The specific technical scheme is as follows:

[0009] A control method for bipolar dual-reaction zone pulse air purification, wherein the device is composed of a bipolar pulse high-voltage power supply and a reactor in the dual-reaction zone, wherein the bipolar pulse high-voltage power supply is composed of an adjustable DC voltage source, a filtering energy storage capacitor, a semiconductor H-bridge pulse generating circuit, a pulse boosting circuit, a positive pulse output high-voltage diode module, a negative pulse output high-voltage diode module and a control system; the bipolar pulse high-voltage power supply has a positive pulse high-voltage output and a negative pulse high-voltage output, and the reactor in the dual-reaction zone is composed of two reaction zones, a positive pulse reaction zone and a negative pulse reaction zone, wherein the positive pulse reaction zone is connected to the positive pulse high-voltage output and is grounded, and the negative pulse reaction zone is connected to the negative pulse high-voltage output and is grounded, and the positive pulse high-voltage output and the negative pulse high-voltage output are independent of each other, and the characteristics of the positive pulse and the negative pulse are used to treat gas pollutants in the corresponding positive pulse reaction zone and the negative pulse reaction zone, and the control system uniformly controls the parameters of the positive pulse and the negative pulse.

[0010] The pulse frequency is adjusted so that the number of positive and negative pulse high-voltage pulses G occurring during the time the gas passes from the inlet to the outlet of the bipolar dual reaction zone satisfies the following two formulas at the same time:

[0011]

[0012]

[0013] Where Q is the total gas flow rate, F is the frequency of positive and negative high-voltage pulses corresponding to the Q flow rate, S is the effective flow cross-section of the gas in the bipolar dual reaction zone, the gas in the positive pulse reaction zone flows through the effective length L1, and the gas in the negative pulse reaction zone flows through the effective length L2, G is the number of positive and negative pulse high-voltage pulses during the time the gas passes from the inlet to the outlet of the bipolar dual reaction zone, ŋ1 is the polluted gas purification rate of a single positive and negative pulse high voltage at the highest operating pulse peak voltage of the reactor in the dual reaction zone, Z is the total efficiency of the reactor in the dual reaction zone, and the Z value is controlled to be 0.99;

[0014] The filtering energy storage capacitor is connected to the adjustable DC voltage source to filter and store charge for the adjustable DC voltage source, and to supply power for the high current pulse output when the semiconductor H-bridge pulse generating circuit is working.

[0015] An air switch is installed on the circuit of the bipolar pulse high voltage power supply to ensure safety. The rated current in the air switch specification is Selected by the following calculation:

[0016] First calculate the circuit current of the bipolar pulse high voltage power supply when the load is short-circuited:

[0017]

[0018] Where t is the time, is the circuit current output by the bipolar pulse power supply at time t, Udc is the voltage of the DC power supply, Rs is the resistance of the pulse transformer coil, and Ls is the leakage inductance of the pulse transformer. is the current at t = 0;

[0019] Then select an air switch so that the rated current in its specifications satisfies < < ;

[0020] The relative deviation between the equivalent capacitance CZ1 of the positive pulse high-voltage output circuit and the equivalent capacitance CZ2 of the negative pulse high-voltage output circuit in the bipolar pulse high-voltage power supply is set within the range of ±10% to maintain the volt-second balance of the magnetic core of the pulse transformer.

[0021] As a preferred solution of the present invention, the calculation of the circuit current when the load of the bipolar pulse high-voltage power supply is short-circuited is simplified to:

[0022]

[0023] where t is time, is the circuit current output by the bipolar pulse power supply at time t, Udc is the voltage of the DC power supply, Rs is the resistance of the pulse transformer coil, and Ls is the leakage inductance of the pulse transformer.

[0024] When the positive pulse reaction area or the negative pulse reaction area is short-circuited, it will cause damage to the semiconductor H-bridge pulse generation circuit. A short-circuit protection capacitor is set. In the connection circuit between the semiconductor H-bridge pulse generation circuit and the pulse transformer, a short-circuit protection capacitor is connected in series. The capacitance value of the short-circuit protection capacitor Cs is controlled as:

[0025] When CZ1 ≥ CZ2, the capacitance value of Cs should be selected to satisfy N 2 × CZ1 ≤ Cs ≤ 2N 2 × CZ1;

[0026] When CZ1 < CZ2, the capacitance value of Cs should be selected to satisfy N 2 × CZ2 ≤ Cs ≤ 2N 2 × CZ2;

[0027] where: N is the turns ratio of the pulse transformer, CZ1 is the equivalent capacitance of the positive pulse reaction area, and CZ2 is the equivalent capacitance of the negative pulse reaction area.

[0028] The control system uses the formula to calculate the safety of the entire system: S = (1 / (1 - (D / (1 - D)) * (Vp / Vn))) * (1 - (P / Pmax)), where S is the safety parameter, D is the duty cycle, Vp is the positive pulse high voltage, Vn is the negative pulse high voltage, P is the system power, and Pmax is the maximum allowable power; the smaller the duty cycle D, the smaller the S, and the safer the system; the smaller the ratio of the positive pulse high voltage to the negative pulse high voltage, the smaller the S, and the safer the system; the smaller the system power, the smaller the S, and the safer the system; when the S value is greater than the preset threshold, the power is turned off to prevent risks.

[0029] The calculation formula for the overall power of the bipolar pulse high-voltage power supply is: P = (Vp * I * (1 - D)) + (Vn *I * D), where P is the overall power, Vp is the positive pulse high voltage, Vn is the negative pulse high voltage, I is the current, and D is the duty cycle; by controlling the positive pulse high voltage, negative pulse high voltage, current, and duty cycle, the overall power can be directly calculated, and then the overall power can be controlled to match the polluted air flow that needs to be treated.

[0030] The overall efficiency of the bipolar pulse high-voltage power supply can be adjusted and optimized. The calculation formula for the overall power of the bipolar pulse high-voltage power supply is: η = (Vp * I * T1) / (Vdc * I * T) * (1 - (Ploss / P)), where η is the efficiency, Vp is the pulse high voltage, I is the current, T1 is the reaction time of the positive pulse reaction zone, Vdc is the DC voltage, T is the period, Ploss is the system loss power, and P is the overall power of the bipolar pulse high-voltage power supply; the efficiency is directly calculated by controlling the pulse high voltage, current, reaction time of the positive pulse reaction zone, DC voltage, and period parameters, and the parameters corresponding to the maximum efficiency are selected as the efficiency optimization parameters.

[0031] The gas flow rate between the two reaction zones of the dual-reaction zone reactor is calculated using the following formula: v = (Vp / A) *(1 - exp(-t / τv)), where v is the gas flow rate, Vp is the pulse high pressure, A is the cross-sectional area of ​​the reaction zone, and τv is the constant of the gas flow rate time.

[0032] The algorithm of the control system to control the pulse output is: if (Vdc >= Vref) then Vp = Vdc * (1 + (D / (1 - D))) else Vp = 0, where Vref is the reference voltage, Vdc is the DC voltage, D is the duty cycle, and Vp is the pulse amplitude.

[0033] Compared with the prior art, the present invention has the following beneficial technical effects:

[0034] 1. A control method for bipolar dual-reaction zone pulse air purification, which adopts two independent pulse outputs of positive pulse high voltage and negative high voltage of a high-voltage power supply, which correspond to the independent positive plasma zone and negative plasma zone inside the reactor respectively, to form positive and negative ion dual purification of polluted gas, improve the purification effect and efficiency, and overcome the defect that traditional gas pollution treatment technology usually adopts a single treatment reaction zone with low efficiency.

[0035] 2. A control method for bipolar dual-reaction zone pulse air purification, which accurately controls the pulse frequency and the flow rate of the treated polluted gas to correspond to a functional relationship in a reasonable area, ensures that the pulse power and the flow rate of the treated polluted gas are in a reasonable matching relationship, thereby ensuring the effective power and greatly increasing the air purification capacity.

[0036] 3. A control method for bipolar dual-reaction zone pulse air purification is proposed, and an accurate calculation method for pulse short-circuit current is proposed, providing a basis for the reasonable selection of specifications of pulse circuit short-circuit protection components.

[0037] 4. A control method for bipolar dual-reaction zone pulse air purification, which adopts an adjustable DC voltage source for power supply and adjusts the peak voltage of independent bipolar pulse high voltage. The size of the pulse peak voltage can be changed according to the change of the insulation strength of the polluted gas, thereby improving the adaptability to the working conditions. The whole operation adopts pulse power supply mode with low energy consumption. The repetition frequency of the independent bipolar pulse high voltage output can further change the pulse repetition frequency according to the change of the working condition of the polluted gas, taking into account both the treatment effect and the operating energy consumption.

[0038] 5. A control method for bipolar dual-reaction zone pulse air purification uses a semiconductor H-bridge pulse generating circuit. A single pulse transformer outputs two independent bipolar pulse high voltages. The circuit is simple and reliable. A suitable load short-circuit protection capacitor is set to improve the reliability of the device while ensuring the performance of the pulse output.

[0039] 6. A control method for bipolar dual reaction zone pulse air purification calculates the safety formula (S = (1 / (1 - (D / (1 - D)) * (Vp / Vn))) * (1 - (P / Pmax))). When the S value is greater than a preset threshold, the power supply is turned off to prevent risks, optimize the control system, and maximize the safety of the treatment process.

[0040] 7. A control method for bipolar dual-reaction zone pulse air purification adopts modular design and a unified control system, which reduces maintenance costs and the frequency of parts replacement. It can be easily expanded to large-scale application scenarios to meet the needs of different users; it adopts a low-noise and low-vibration design to reduce the impact of noise and vibration on the environment, and can minimize the generation of secondary pollutants to ensure the environmental protection and sustainability of the treatment process. At the same time, the device can also reuse some waste materials and exhaust gases, further reducing the negative impact on the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The invention discloses a circuit schematic diagram of a control method for a bipolar dual-reaction zone pulse air purification.

[0042] Figure 2 The invention discloses a bipolar pulse high voltage power supply waveform diagram in a control method of a bipolar dual reaction zone pulse air purification.

[0043] Figure 3 It is a control method for bipolar dual-reaction zone pulse air purification. When the load is short-circuited, there is no short-circuit protection capacitor, and the bipolar pulse power semiconductor H-bridge pulse generating circuit flows through the current waveform.

[0044] Figure 4 It is a control method for bipolar dual-reaction zone pulse air purification. When the load is short-circuited, there is a short-circuit protection capacitor, and a bipolar pulse power semiconductor H-bridge pulse generating circuit flows through the current waveform.

[0045] Figure 5 The invention relates to a control method for bipolar dual reaction zone pulse air purification with a circuit schematic diagram of capacitor short circuit protection.

[0046] Figure 6 The present invention is a structural diagram of a reactor used in a control method for a bipolar dual-reaction zone pulse air purification.

[0047] Figure 7 It is a positive polarity voltage discharge voltammetric curve (voltage / kV is a positive value) at different discharge distances in a control method for a bipolar dual-reaction zone pulse air purification.

[0048] Figure 8 It is a negative polarity voltage discharge voltammetric curve (voltage / kV is a negative value) at different discharge distances in a control method for a bipolar dual-reaction zone pulse air purification.

[0049] Fig. 9 The present invention is a logic architecture diagram of a control method for a bipolar dual-reaction zone pulse air purification.

[0050] In the figure: UP1 is the positive pulse high-voltage peak voltage, UP2 is the negative pulse high-voltage peak voltage, IP1 is the positive pulse output current, IP2 is the negative pulse output current, C1 is the filter energy storage capacitor, DC1 is the adjustable DC voltage source, TR1 is the pulse transformer, D1 is the positive pulse output high-voltage diode module, D2 is the negative pulse output high-voltage diode module, FZ1 is the positive pulse reaction zone, FZ2 is the negative pulse reaction zone, Cs is the short-circuit protection capacitor, VT1, VT2, VT3, VT4 are power semiconductor modules, 1 is the inlet of the polluted gas of the reactor, 2 is the positive pulse reaction zone, 3 is the connection interface between the reactor and the positive high-voltage pulse output and the negative high-voltage pulse output of the pulse power supply, 4 is the negative pulse reaction zone, and 5 is the gas outlet after the reactor is purified. DETAILED DESCRIPTION

[0051] A control method for bipolar dual-reaction zone pulse air purification is mainly composed of a bipolar pulse high-voltage power supply and a dual-reaction zone reactor. The bipolar pulse high-voltage power supply includes two independent pulse outputs of positive pulse high voltage and negative high voltage, and is connected to the load through three connection points of positive pulse, negative pulse and ground. The bipolar pulse high-voltage power supply is composed of an adjustable DC voltage source, a filter energy storage capacitor, a semiconductor H-bridge pulse generating circuit, a pulse boosting circuit, a positive pulse output high-voltage diode module, a negative pulse output high-voltage diode module, and a control system. The dual-reaction zone reactor is composed of two reaction zones, a positive pulse reaction zone and a negative pulse reaction zone. The two reaction zones are respectively connected to the two independent pulse outputs and ground of the bipolar pulse high-voltage power supply.

[0052] The adjustable DC voltage source provides power for a control method of bipolar dual-reaction zone pulse air purification. The DC voltage value of the adjustable DC voltage source is controlled by the control system. The control system can change the size of the bipolar pulse high voltage peak voltage by adjusting the size of the DC voltage value according to the load operation needs, thereby improving the adaptability to different working conditions.

[0053] Filter energy storage capacitor: connected to the adjustable DC voltage source, the function of the capacitor is to filter the adjustable DC voltage source and to store energy charge. When the semiconductor H-bridge pulse generating circuit is working, it provides power for the high current pulse output.

[0054] Semiconductor H-bridge pulse generating circuit: mainly composed of power semiconductor modules and drive circuits, connected to filter energy storage capacitors, used to generate bipolar pulse high voltage output. The semiconductor H-bridge pulse generating circuit is controlled by two drive signals of the control system, one drive signal is used to generate positive pulse high voltage output, and the other drive signal is used to generate negative pulse high voltage output. At the same time, the two drive signals can also control the repetition frequency of the bipolar pulse high voltage output.

[0055] Pulse boost circuit: mainly composed of a pulse transformer, which contains leakage inductance. The primary of the pulse transformer coil is connected to the semiconductor H-bridge pulse generating circuit. The input is a low-voltage pulse. Through the magnetic core coupling, the secondary output of the pulse transformer coil is a high-voltage pulse. One end of the secondary coil of the pulse transformer is grounded, and the other end is connected to the positive pulse output high-voltage diode module and the negative pulse output high-voltage diode module at the same time.

[0056] Positive pulse output high-voltage diode module: The positive pole of the high-voltage diode module is connected to the secondary output of the pulse transformer coil, and the negative pole of the high-voltage diode module is led out through the high-voltage positive pulse connection point, which is connected to the connection point of the discharge electrode of the positive pulse reactor through a wire. The other electrode of the positive pulse reactor is grounded. The high-voltage positive pulse connection point and the discharge electrode connection point of the positive pulse reactor generally adopt the high-voltage porcelain bottle output method.

[0057] Negative pulse output high-voltage diode module: The cathode of the high-voltage diode module is connected to the secondary output of the pulse transformer coil, and the anode of the high-voltage diode module is led out through the high-voltage negative pulse connection point, which is connected to the connection point of the discharge electrode of the negative pulse reactor through a wire. The other electrode of the negative pulse reactor is grounded. The high-voltage negative pulse connection point and the discharge electrode connection point of the negative pulse reactor generally adopt the high-voltage porcelain bottle output method.

[0058] Double reaction zone reactor: It consists of two reaction zones, the positive pulse reaction zone and the negative pulse reaction zone. The two reaction zones are respectively connected to two independent pulse outputs of a bipolar pulse high voltage power supply. The positive pulse high voltage generates a positive plasma zone in the positive pulse reaction zone, and the negative pulse high voltage generates a negative plasma zone in the positive pulse reaction zone. The plasma discharge will generate free radicals, active oxides, high-energy electrons and ions, which will react with organic pollutant molecules, oxidize, crack and reorganize the chemical molecules of these pollutants, and finally decompose the organic pollutants into harmless substances. At the same time, bacteria and viruses can also be inactivated and killed. The polluted gas flows through the positive plasma zone and the negative plasma zone of the double reaction zone reactor for double purification, so that the purified polluted gas meets the emission standards.

[0059] Control driving method: DC power supply voltage Udc, one drive is used to generate a positive pulse high voltage output drive signal PWM1, drive pulse width Pw1, another drive is used to generate a negative pulse high voltage output drive signal PWM2, drive pulse width Pw2, pulse transformer leakage inductance Ls, pulse transformer coil resistance Rs, pulse transformer ratio N, positive pulse reaction area equivalent capacitance CZ1, negative pulse reaction area equivalent capacitance CZ2. Then:

[0060] Positive pulse high voltage output drive signal PWM1, drive pulse width ;

[0061] Negative pulse high voltage output drive signal PWM2, drive pulse width ;

[0062] At this time, the positive pulse high-voltage output drive signal PWM1 and the negative pulse high-voltage output drive signal PWM2 can both achieve zero current shutdown, reducing the switching transient loss when the semiconductor H-bridge pulse generating circuit is working. At the same time, the pulse output peak voltage reaches the maximum value under the current DC power supply voltage Udc.

[0063] When the positive pulse high voltage output drive signal PWM1, the drive pulse width , negative pulse high voltage output drive signal PWM2, drive pulse width When the pulse output peak voltage cannot reach the maximum value under the current DC power supply voltage Udc.

[0064] The pulse frequency is adjusted by the positive and negative pulse drive signals PWM1 and PWM2, so that the number of positive and negative pulse high-voltage pulses G occurring during the time when the gas passes from the inlet to the outlet of the bipolar dual reaction zone satisfies the following two formulas at the same time:

[0065]

[0066]

[0067] Where Q is the total gas flow rate, F is the frequency of positive and negative high-voltage pulses corresponding to the Q flow rate, S is the effective flow cross-section of the gas in the bipolar dual reaction zone, the gas in the positive pulse reaction zone flows through the effective length L1, and the gas in the negative pulse reaction zone flows through the effective length L2, G is the number of positive and negative pulse high-voltage pulses during the time the gas passes from the inlet to the outlet of the bipolar dual reaction zone, ŋ1 is the polluted gas purification rate of a single positive and negative pulse high voltage at the highest operating pulse peak voltage of the reactor in the dual reaction zone, Z is the total efficiency of the reactor in the dual reaction zone, and the Z value is controlled to be 0.99;

[0068] In practical applications, the instrument measures the polluted gas purification rate ŋ1 of a single positive and negative pulse high voltage in the dual reaction zone reactor under the current operating conditions and at the highest operating pulse peak voltage. Assuming that the measured single pulse gas purification rate ŋ1 is 0.05, if the total efficiency of the reactor is to reach 0.99, the number of positive and negative pulse high voltage pulses occurring during the time the gas passes from the inlet to the outlet of the bipolar dual reaction zone is about 90 times. Assuming that the effective flow cross section S of the reactor gas is 2 square meters, the effective length L1 of the gas flow in the positive pulse reaction zone is 1 meter, the effective length L2 of the gas flow in the negative pulse reaction zone is 1 meter, and the total gas flow Q is 20 cubic meters per second, the pulse frequency should be adjusted to be greater than or equal to 450HZ. .

[0069] In order to maintain the volt-second balance of the pulse transformer's core, the relative deviation of the equivalent capacitance CZ1 in the positive pulse reaction zone and the equivalent capacitance CZ2 in the negative pulse reaction zone is set within the range of ±10%.

[0070] When the bipolar pulse high voltage power supply is short-circuited, the current will increase sharply, so an air switch is set to ensure safety. The rated current in the air switch specification is Selected by the following calculation:

[0071] First calculate the circuit current of the bipolar pulse high voltage power supply when the load is short-circuited:

[0072]

[0073] Where t is the time, is the circuit current output by the bipolar pulse power supply at time t, Udc is the DC power supply voltage, Rs is the pulse transformer coil resistance, Ls is the pulse transformer leakage inductance, is the current when t is 0;

[0074] Then select the air switch so that the rated current in its specifications satisfy < < .

[0075] Initial current of the inductor in the loop Equal to zero (i.e. the current at t=0), when the load is short-circuited, the circuit current calculation is simplified to:

[0076]

[0077] When the positive pulse reaction area is short-circuited, the maximum peak current is:

[0078]

[0079] When the negative pulse reaction area is short-circuited, the maximum peak current is:

[0080]

[0081] Among them, Udc is the DC power supply voltage, Rs is the pulse transformer coil resistance, Ls is the pulse transformer leakage inductance, Pw1 is the pulse of pulse width modulation PWM1, and Pw2 is the pulse of pulse width modulation PWM2.

[0082] When the positive pulse reaction area or the negative pulse reaction area is short-circuited, the current increases sharply, exceeding the maximum allowable peak current of the semiconductor H-bridge pulse generation circuit, resulting in damage to the semiconductor H-bridge pulse generation circuit. Therefore, short-circuit protection is required. A capacitor can be connected in series in the circuit connecting the semiconductor H-bridge pulse generation circuit and the pulse transformer for short-circuit protection. The selection of the capacitance value of the short-circuit protection capacitor Cs is related to the equivalent capacitance value CZ1 of the positive pulse reaction area and the equivalent capacitance value CZ2 of the negative pulse reaction area.

[0083] When CZ1 ≥ CZ2, the selection of the capacitance value of Cs should satisfy N 2 × CZ1 ≤ Cs ≤ 2N 2 × CZ1;

[0084] When CZ1 < CZ2, the selection of the capacitance value of Cs should satisfy N 2 × CZ2 ≤ Cs ≤ 2N 2 × CZ2;

[0085] Where: N is the turns ratio of the pulse transformer, CZ1 is the equivalent capacitance value of the positive pulse reaction area, and CZ2 is the equivalent capacitance value of the negative pulse reaction area.

[0086] When the selected value of the capacitance of Cs is too small, at the same DC power supply voltage Udc, it will cause insufficient pulse output power and too small output peak voltage.

[0087] When the selected value of the capacitance of Cs is too large, at the same DC power supply voltage Udc, it will cause poor protection effect when the load is short-circuited.

[0088] The control system uses a formula to calculate the safety of the entire system: S = (1 / (1 - (D / (1 - D)) * (Vp / Vn))) * (1 - (P / Pmax)), where S is the safety parameter, D is the duty cycle, Vp is the positive pulse high voltage, Vn is the negative pulse high voltage, P is the system power, and Pmax is the maximum allowable power; thus, the smaller the duty cycle D, the smaller S and the safer the system; the smaller the ratio of the positive pulse high voltage to the negative pulse high voltage, the smaller S and the safer the system; the smaller the system power, the smaller S and the safer the system. When the value of S is greater than the pre-set threshold, the power supply is turned off to prevent risks.

[0089] The calculation formula for the overall power of the bipolar pulse high voltage power supply is: P = (Vp * I * (1 - D)) + (Vn * I * D), where P is the overall power, Vp is the positive pulse high voltage, Vn is the negative pulse high voltage, I is the current, and D is the duty cycle; by controlling the positive pulse high voltage, negative pulse high voltage, current, and duty cycle, the overall power can be directly calculated, and then the overall power can be controlled to match the flow rate of the contaminated air to be processed.

[0090] The overall efficiency of the bipolar pulse high-voltage power supply can be adjusted and optimized. The calculation formula for the overall power of the bipolar pulse high-voltage power supply is: η = (Vp * I * T1) / (Vdc * I * T) * (1 - (Ploss / P)), where η is the efficiency, Vp is the pulse high voltage, I is the current, T1 is the reaction time of the positive pulse reaction zone, Vdc is the DC voltage, T is the period, Ploss is the system loss power, and P is the overall power of the bipolar pulse high-voltage power supply; the efficiency is directly calculated by controlling the pulse high voltage, current, reaction time of the positive pulse reaction zone, DC voltage, and period parameters, and the parameters corresponding to the maximum efficiency are selected as the efficiency optimization parameters.

[0091] The gas flow rate between the two reaction zones of the dual-reaction zone reactor is calculated using the following formula: v = (Vp / A) *(1 - exp(-t / τv)), where v is the gas flow rate, Vp is the pulse high pressure, A is the cross-sectional area of ​​the reaction zone, and τv is the constant of the gas flow rate time.

[0092] The algorithm of the control system to control the pulse output is: if (Vdc >= Vref) then Vp = Vdc * (1 + (D / (1 - D))) else Vp = 0, where Vref is the reference voltage, Vdc is the DC voltage, D is the duty cycle, and Vp is the pulse amplitude.

[0093] A specific embodiment

[0094] A control method for bipolar dual reaction zone pulse air purification, having an implemented circuit principle such as Figure 1 shown.

[0095] DC1 is an adjustable DC voltage source, which provides power for a control method of bipolar dual reaction zone pulse air purification. The DC voltage value of the adjustable DC voltage source is controlled by the control system, and the control system can change the size of the bipolar pulse high voltage peak voltage UP1 and UP2 by adjusting the size of the DC voltage value according to the load operation needs.

[0096] C1 is a filtering energy storage capacitor, which is connected to the DC1 adjustable DC voltage source. The capacitor's functions are to filter the adjustable DC voltage source and to store energy charges. When the H-bridge pulse generating circuit composed of VT1, VT2, VT3, and VT4 power semiconductor modules is working, it provides power for the high-current pulse output.

[0097] The semiconductor H-bridge pulse generating circuit is mainly composed of VT1, VT2, VT3, VT4 power semiconductor modules and drivers PWM1 and PWM2. It is connected to the filter energy storage capacitor C1 to generate bipolar pulse high voltage output. The semiconductor H-bridge pulse generating circuit is controlled by the two-way drive PWM1 and PWM2 of the control system. PWM1 is used to drive VT1 and VT4 power semiconductor modules to generate positive pulse high voltage output, and PWM2 is used to drive VT2 and VT3 power semiconductor modules to generate negative pulse high voltage output. At the same time, the two-way drive PWM1 and PWM2 can also control the repetition frequency of the bipolar pulse high voltage output, and the pulse repetition frequency can be changed according to the changes in the polluted gas, taking into account the treatment effect and operating energy consumption.

[0098] The pulse boost circuit is mainly composed of a pulse transformer TR1, and the inductor Ls is the leakage inductance of the pulse transformer. The primary of the pulse transformer coil is connected to the semiconductor H-bridge pulse generating circuit composed of VT1, VT2, VT3, and VT4 power semiconductor modules. The input is a low-voltage pulse, and through the magnetic core coupling, the secondary output of the pulse transformer coil is a high-voltage pulse. One end of the secondary coil of the pulse transformer is led out and grounded through the grounding point 3. The other end is simultaneously connected to the positive pulse output high-voltage diode module D1 and the negative pulse output high-voltage diode module D2.

[0099] One end of the secondary coil of the bipolar pulse high voltage power supply pulse transformer is grounded at point 3.

[0100] The positive pole of the D1 diode module is connected to the secondary output of the pulse transformer TR1 coil, and the negative pole of the D1 diode module is led out through the high-voltage positive pulse connection point 1, and the high-voltage positive pulse connection point 1 is connected to the connection point of the discharge electrode of the positive pulse reactor FZ1 through a wire.

[0101] The cathode of the D2 diode module is connected to the secondary output of the pulse transformer TR1 coil, and the anode of the D2 diode module is led out through the high-voltage negative pulse connection point 2. The high-voltage positive pulse connection point 2 is connected to the connection point of the discharge electrode of the positive pulse reactor FZ2 through a wire.

[0102] The double reaction zone reactor consists of two reaction zones: positive pulse reaction zone FZ1 and negative pulse reaction zone FZ2. Figure 1 The positive pulse reaction zone FZ1 and the negative pulse reaction zone FZ2 are equivalent circuit diagrams of the reaction zone. Figure 6A control method for bipolar dual-reaction zone pulse air purification Reactor structure diagram. In the positive pulse reaction zone FZ1, the equivalent capacitor CZ1 is connected in parallel with a series circuit of a bidirectional voltage regulator diode DZ1 and a variable resistor RZ1. The equivalent capacitor CZ1 is the capacitance characteristic presented by the mechanical structure of the positive pulse reaction zone FZ1, and the design of the pulse generating circuit is closely related to the equivalent capacitor CZ1. The series circuit of the bidirectional voltage regulator diode DZ1 and the variable resistor RZ1 is the discharge characteristic exhibited by different discharge electrode shapes and distances in the positive pulse reaction zone FZ1. The bidirectional voltage regulator diode DZ1 represents the starting discharge voltage value, and the variable resistor RZ1 represents different voltages corresponding to different currents, which changes nonlinearly. In the negative pulse reaction zone FZ2, the equivalent capacitor CZ2 is connected in parallel with a series circuit of a bidirectional voltage regulator diode DZ2 and a variable resistor RZ2. The equivalent capacitor CZ2 is the capacitance characteristic presented by the mechanical structure of the negative pulse reaction zone FZ2, and the design of the pulse generating circuit is closely related to the equivalent capacitor CZ2. The series circuit of the bidirectional voltage regulator diode DZ2 and the variable resistor RZ2 is the discharge characteristic of the different discharge electrode shapes and distances of the negative pulse reaction zone FZ2. The bidirectional voltage regulator diode DZ2 represents the starting discharge voltage value, and the variable resistor RZ2 represents different voltages corresponding to different currents, which changes nonlinearly. Due to the different high-voltage discharge voltammetric curves of the positive pulse and the negative pulse, the internal discharge distances of the positive pulse reaction zone FZ1 and the negative pulse reaction zone FZ2 are not equal. With the same discharge distance, the positive pulse is more likely to have a high-voltage breakdown. Therefore, the internal discharge distance of the positive pulse reaction zone FZ1 is greater than the internal discharge distance of the negative pulse reaction zone FZ2. The two reaction zones are respectively connected to the two independent pulse outputs 1 and 2 of the bipolar pulse high-voltage power supply. The other electrode of the negative pulse reactor is grounded and the other electrode of the positive pulse reactor is grounded, and is connected to the ground of the bipolar pulse high-voltage power supply. The UP1 positive pulse high voltage produces a positive plasma zone in the positive pulse reaction zone FZ1, and the UP2 negative pulse high voltage produces a negative plasma zone in the positive pulse reaction zone FZ2. The polluted gas flows through the positive plasma zone and the negative plasma zone of the dual reaction zone reactor for double purification, so that the purified polluted gas meets the emission standards.

[0103] Bipolar pulse high voltage power supply waveform diagram, such as Figure 2 shown.

[0104] UP1 is the positive pulse high voltage power supply output waveform when the pulse power supply supplies power to the positive pulse reaction zone FZ1, which is used to form a positive plasma zone. UP2 is the negative pulse high voltage power supply output waveform when the pulse power supply supplies power to the negative pulse reaction zone FZ2, which is used to form a negative plasma zone. IP1 is the positive pulse current output, corresponding to PWM1 driving VT1 and VT4 power semiconductor modules to generate positive pulse high voltage pulse output current. IP2 is the negative pulse current output, and PWM2 drives VT2 and VT3 power semiconductor modules to generate negative pulse high voltage pulse output current.

[0105] When there is a short circuit in the load, with or without a short-circuit protection capacitor, the difference in the current I1 flowing through the power semiconductor modules VT1, VT2, VT3, and VT4 is as shown in: Figure 3 When there is a short circuit in the load and there is no short-circuit protection capacitor, the current waveform flowing through the bipolar pulse power semiconductor H-bridge pulse generation circuit Figure 4 When there is a short circuit in the load and there is a short-circuit protection capacitor, the current waveform flowing through the bipolar pulse power semiconductor H-bridge pulse generation circuit. When there is a short circuit in the load, the short-circuit current flowing through the power semiconductor modules VT1, VT2, VT3, and VT4 is 2.5 to 5 times larger in the circuit without a short-circuit protection capacitor than in the circuit with a short-circuit protection capacitor. Therefore, it is necessary to select a suitable short-circuit protection capacitor.

[0106] For the setting of the short-circuit protection capacitor for load short circuit, see Figure 5 , the selection of the capacitance value of the short-circuit protection capacitor Cs is related to the equivalent capacitance CZ1 in the positive pulse reaction region and the equivalent capacitance CZ2 in the negative pulse reaction region. When CZ1 ≥ CZ2, the capacitance value of Cs should satisfy N 2 × CZ1 ≤ Cs ≤ 2N 2 × CZ1; when CZ1 < CZ2, the capacitance value of Cs should satisfy N 2 × CZ2 ≤ Cs ≤ 2N 2 × CZ2; if the selected value of the capacitance of Cs is too small, at the same DC power supply voltage Udc, it will result in insufficient pulse output power and too small output peak voltage. If the selected value of the capacitance of Cs is too large, at the same DC power supply voltage Udc, it will result in poor protection effect during load short circuit.

[0107] For the structure diagram of the double reaction zone device reactor, see Figure 6 , 1 is the inlet of the polluted gas of the reactor; 2 is the positive plasma region of the reactor, corresponding to Figure 1 the positive pulse reaction region FZ1. After inputting a positive high-voltage pulse, a positive plasma region is formed; 3 is the connection interface between the reactor and the positive high-voltage pulse output and negative high-voltage pulse output of the pulse power supply, with a connection flange opening for the pulse power supply. The connection point 1 of the positive high-voltage pulse output of the pulse power supply UP1 is connected to the + connection point of the reactor, the connection point 2 of the negative high-voltage pulse output of the pulse power supply UP2 is connected to the - connection point of the reactor, and the grounding connection point 3 of the pulse power supply is connected to the GND connection point of the reactor; 4 is the negative plasma region of the reactor, corresponding to Figure 1 the negative pulse reaction region FZ2 as the reaction region. After inputting a negative high-voltage pulse, a negative plasma region is formed; 5 is the outlet of the purified gas of the reactor.

[0108] The discharge curve of the positive plasma region 2 of the reactor is shown in Figure 7 The positive voltage discharge volt-ampere curve at different discharge distances, for the negative plasma region 4 of the reactor, see Figure 8Negative voltage discharge voltammetry curves at different discharge distances. Different from the high voltage discharge voltammetry curves of positive and negative pulses, the breakdown voltage of negative polarity at the same distance is much greater than the breakdown voltage of positive polarity. Therefore, the internal discharge distances of the positive plasma zone 2 and the negative plasma zone 4 of the same reactor are not equal, and the electrode shapes are different. The internal discharge distance of the positive plasma zone 2 of the reactor is greater than the internal discharge distance of the negative plasma zone 4 of the reactor.

[0109] Special statement: The "embodiment" and the like described in this specification refer to the specific features, elements or characteristics described in conjunction with the embodiment included in the embodiment generally described in this application. The appearance of the same expression in multiple places in the specification does not limit the specific reference to the same embodiment. In other words, when describing a specific feature, element or characteristic in conjunction with any embodiment, it is claimed that such feature, element or characteristic is implemented in conjunction with other embodiments and is included in the scope of the claims for protection of the present invention; The embodiment describes the present invention with reference to multiple explanatory embodiments of the logical architecture and ideas of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art can design many other modifications and implementation methods within the framework of the technical solution of the present invention, and can make various non-essential modifications and improvements to the key points of the technical solution. For those skilled in the art, other uses will also be obvious, and non-substantial changes or replacements that can be easily thought of for implementation will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A control method for bipolar dual-reaction zone pulse air purification, wherein the device is composed of a bipolar pulse high-voltage power supply and a reactor in a dual-reaction zone, wherein the bipolar pulse high-voltage power supply is composed of an adjustable DC voltage source, a filter energy storage capacitor, a semiconductor H-bridge pulse generating circuit, a pulse boosting circuit, a positive pulse output high-voltage diode module, a negative pulse output high-voltage diode module and a control system; the bipolar pulse high-voltage power supply has a positive pulse high-voltage output and a negative pulse high-voltage output, and is characterized in that: The double-reaction zone reactor consists of two reaction zones, a positive pulse reaction zone and a negative pulse reaction zone. The positive pulse reaction zone is connected to the positive pulse high-voltage output and grounded, and the negative pulse reaction zone is connected to the negative pulse high-voltage output and grounded. The positive pulse high-voltage output and the negative pulse high-voltage output are independent of each other. The characteristics of the positive pulse and the negative pulse are used to treat gaseous pollutants in the corresponding positive pulse reaction zone and the negative pulse reaction zone, and the control system uniformly controls the parameters of the positive pulse and the negative pulse. The pulse frequency is adjusted so that the number of positive and negative pulse high-voltage pulses G occurring during the time the gas passes from the inlet to the outlet of the bipolar dual reaction zone satisfies the following two formulas at the same time: Where Q is the total gas flow rate, F is the frequency of positive and negative high-voltage pulses corresponding to the Q flow rate, S is the effective flow cross-sectional area of ​​the gas in the bipolar dual reaction zone, the gas in the positive pulse reaction zone flows through the effective length L1, and the gas in the negative pulse reaction zone flows through the effective length L2, G is the number of positive and negative pulse high-voltage pulses during the time the gas passes from the inlet to the outlet of the bipolar dual reaction zone, ŋ1 is the polluted gas purification rate of a single positive and negative pulse high voltage at the highest operating pulse peak voltage of the reactor in the dual reaction zone, Z is the total efficiency of the reactor in the dual reaction zone, and the Z value is controlled to be 0.99; The filtering energy storage capacitor is connected to the adjustable DC voltage source to filter and store charge for the adjustable DC voltage source, and to supply power for the high current pulse output when the semiconductor H-bridge pulse generating circuit is working.

2. According to claim 1, a control method for bipolar dual-reaction zone pulse air purification is characterized in that: An air switch is set on the circuit of the bipolar pulse high voltage power supply to ensure safety. The rated current in the air switch specification is To select the bipolar pulse high voltage power supply, first calculate the circuit current when the load is short-circuited: Where t is the time, is the circuit current output by the bipolar pulse power supply at time t, Udc is the DC power supply voltage, Rs is the pulse transformer coil resistance, Ls is the pulse transformer leakage inductance, is the current when t is 0; then select the air switch so that the rated current in its specification satisfy < < .

3. The control method of a bipolar dual-reaction zone pulse air purification according to claim 1, characterized in that: The relative deviation of the equivalent capacitance CZ1 of the positive pulse high voltage output circuit and the equivalent capacitance CZ2 of the negative pulse high voltage output circuit in the bipolar pulse high voltage power supply is set within the range of ±10% to ensure the volt-second balance of the magnetic core of the pulse transformer.

4. The control method of a bipolar dual-reaction zone pulse air purification according to claim 1, characterized in that: A pulse current detection is set on the primary connection line of the pulse transformer between the semiconductor H-bridge pulse generating circuit and the pulse boosting circuit. When the peak value of the detected pulse current exceeds the maximum allowable current value of the semiconductor module of the H-bridge pulse generating circuit, the short-circuit protection is triggered, and the trigger pulse of the H-bridge pulse generating circuit is immediately forced to be closed.

5. The control method of a bipolar dual-reaction zone pulse air purification according to claim 1, characterized in that: When the positive pulse reaction area or the negative pulse reaction area is short-circuited, the semiconductor H-bridge pulse generating circuit will be damaged. A short-circuit protection capacitor is set. In the connection loop between the semiconductor H-bridge pulse generating circuit and the pulse transformer, a short-circuit protection capacitor is connected in series. The capacitance value of the short-circuit protection capacitor Cs is controlled as follows: When CZ1≥CZ2, the capacitance value of Cs should satisfy N 2 ×CZ1≤Cs≤2N 2 ×CZ1; When CZ1 < CZ2, the Cs capacitance value selection should satisfy N 2 ×CZ2 ≤ Cs ≤ 2N 2 ×CZ2; Where: N is the pulse transformer ratio, CZ1 is the equivalent capacitance of the positive pulse reaction zone, and CZ2 is the equivalent capacitance of the negative pulse reaction zone.

6. The control method of a bipolar dual-reaction zone pulse air purification according to claim 1, characterized in that: The control system uses the formula to calculate the safety of the entire system: S = (1 / (1 - (D / (1 - D)) * (Vp / Vn))) * (1 - (P / Pmax)), where S is a safety parameter, D is a duty cycle, Vp is a positive pulse high voltage, Vn is a negative pulse high voltage, P is a system power, and Pmax is a maximum allowable power; in this way, the smaller the duty cycle D, the smaller the S, and the safer the system; the smaller the ratio of the positive pulse high voltage to the negative pulse high voltage, the smaller the S, and the safer the system; the smaller the system power and the smaller the S, the safer the system; when the S value is greater than a preset threshold, the power is turned off to prevent risks.

7. The control method of bipolar dual reaction zone pulse air purification according to claim 1, characterized in that: The calculation formula for the overall power of the bipolar pulse high-voltage power supply is: P = (Vp * I * (1 - D)) + (Vn * I *D), where P is the overall power, Vp is the positive pulse high voltage, Vn is the negative pulse high voltage, I is the current, and D is the duty cycle; by controlling the positive pulse high voltage, negative pulse high voltage, current, and duty cycle, the overall power can be directly calculated, and then the overall power can be controlled to match the polluted air flow rate that needs to be treated.

8. The control method of a bipolar dual-reaction zone pulse air purification according to claim 1, characterized in that: The overall efficiency of the bipolar pulse high-voltage power supply can be adjusted and optimized, and the calculation formula for the overall power of the bipolar pulse high-voltage power supply is: η = (Vp * I * T1) / (Vdc * I * T) * (1 - (Ploss / P)), wherein η is the efficiency, Vp is the pulse high voltage, I is the current, T1 is the reaction time of the positive pulse reaction zone, Vdc is the DC voltage, T is the period, Ploss is the system loss power, and P is the overall power of the bipolar pulse high-voltage power supply; the efficiency is directly calculated by controlling the pulse high voltage, current, the reaction time of the positive pulse reaction zone, the DC voltage, and the period parameters, and the parameters corresponding to the maximum efficiency are selected as the efficiency optimization parameters.

9. The control method of bipolar dual reaction zone pulse air purification according to claim 1, characterized in that: The gas flow rate between the two reaction zones of the dual-reaction zone reactor is calculated using the following formula: v = (Vp / A) * (1 -exp(-t / τv)), where v is the gas flow rate, Vp is the pulse high pressure, A is the cross-sectional area of ​​the reaction zone, and τv is the constant of the gas flow rate time.

10. The control method of bipolar dual reaction zone pulse air purification according to claim 1, characterized in that: The algorithm of the control system for controlling pulse output is: if (Vdc >= Vref) then Vp = Vdc * (1 + (D / (1- D))) else Vp = 0, where Vref is the reference voltage, Vdc is the DC voltage, D is the duty cycle, and Vp is the pulse amplitude.

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