Constant-current high-frequency high-voltage direct-current pulse power supply applied to electrostatic dust collection and implementation method thereof

Abstract

The invention belongs to the technical field of direct-current pulse power supply systems, and provides a constant-current high-frequency high-voltage direct-current pulse power supply applied to electrostatic dust collection and an implementation method thereof. The device comprises a pulse high-voltage generation circuit, a driving circuit and a control system, the pulse high-voltage generation circuit comprises a primary filter rectifier module, a high-frequency inverter circuit, a high-frequency voltage transformer T and a voltage doubling rectifier circuit; a driving circuit; according to the implementation method of the high-frequency and high-voltage direct-current pulse power supply, three-phase 380V input is subjected to controllable rectification, high-frequency inversion, boosting through the ferrite transformer and voltage doubling rectification to obtain direct-current pulse high-voltage output, the power supply works stably, the pulse voltage is high, electricity is saved by about 40% when the power supply is applied to the aspect of environmental protection, and the application range is wide. The device can be widely applied to environment-friendly equipment for smoke removal, dust removal, odor removal, moisture removal and the like under working conditions, and is remarkable in effect, stable in quality and obvious in electricity-saving effect; on the other hand, through two-stage detection and fault judgment, the pulse power supply can be well controlled and protected.

Description

Technical Field

[0001] The present invention belongs to the technical field of direct current pulse power supply systems, and in particular, relates to a constant current, high frequency, high voltage direct current pulse power supply for electrostatic dust removal and a method for realizing the same. Background Art

[0002] Electrostatic precipitators are widely used in the field of industrial waste gas treatment. Among the many dust removal methods, they are widely praised by the industry for their many advantages such as simplicity, high efficiency and easy maintenance. Compared with traditional industrial frequency power supplies and high-frequency power supplies, pulse dust collectors use high-voltage pulses to charge dust in a short period of time, making it easier to remove fine particles, especially high-resistance fine dust particles, effectively suppress back corona, and achieve low exhaust gas emissions; at the same time, pulse power supplies are more energy-efficient and are a research hotspot in the field of electrostatic precipitators at home and abroad. The inventors of this application have found that in actual applications, the existing technology mainly has the following deficiencies: the control and protection of the pulse power supply is poor, and the power supply is easily damaged; on the other hand, the secondary side energy storage time of the pulse power supply is short, resulting in a low pulse voltage. Summary of the invention

[0003] The purpose of the present invention is to provide a constant current high frequency high voltage direct current pulse power supply for electrostatic precipitator to solve the technical problems existing in the prior art.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A constant current high-frequency high-voltage direct current pulse power supply for electrostatic dust removal comprises a pulse high-voltage generating circuit, a driving circuit and a control system; the pulse high-voltage generating circuit comprises a primary filtering and rectifying module, a high-frequency inverter circuit, a high-frequency voltage transformer T and a voltage doubling rectifier circuit, the high-frequency inverter circuit adopts an H-bridge high-frequency inverter circuit, which is combined with a capacitor C3, a capacitor C2 and an inductor L1 to form an LCC resonant converter; the driving circuit is used to receive a PWM signal from a main control chip to drive the pulse high-voltage generating circuit; the control system comprises a main control MCU, a signal sampling and processing module, a fault judgment module, a voltage regulating pulse control module and a power supply; the voltage regulating pulse control module, when it is judged that a fault occurs, is used to reduce the duty cycle of the PWM signal and enter a delay at the same time, and reduce the peak voltage output of the pulse generating circuit, and after the delay, start the normal PWM driving signal generation.

[0005] Furthermore, the main control chip of the main control MCU adopts a model of dsPIC33AK128MC102; the primary filter rectifier module adopts a three-phase controllable rectifier module MDS.

[0006] Furthermore, the H-bridge high-frequency inverter circuit includes four groups of IGBTs (Q1, Q2, Q3, Q4).

[0007] Furthermore, the drive circuit includes a four-way IGBT drive circuit, which includes a drive chip U1 (HCPL316), wherein pin 1 of the drive chip U1 is connected to the PWM pin of the main control MCU, pin 5 is connected to the REST pin of the main control MCU, pin 6 is connected to the FAULT pin of the main control MCU, pin 14 is connected to the IGBT collector via resistor R3 and diode D2, pin 11 is connected to the IGBT gate via resistor R6, and pin 16 is connected to the IGBT emitter.

[0008] Furthermore, the voltage doubler rectifier circuit includes a diode D1, a diode D2, a capacitor C4, and a capacitor C5.

[0009] Furthermore, the high-frequency transformer T is a ferrite transformer.

[0010] Furthermore, the signal sampling and processing module is used to sample and process: primary side current, primary side voltage, secondary side voltage, and secondary side current.

[0011] Furthermore, the fault judgment module includes a primary side current and voltage fault judgment module and a secondary side current and voltage fault judgment module.

[0012] In order to achieve the above-mentioned purpose, the present invention also provides a method for realizing a constant current, high frequency, high voltage DC pulse power supply for electrostatic dust removal, wherein a three-phase 380V input is controlledly rectified, and then a high frequency inverter is used to boost the voltage through a ferrite transformer, and then a DC pulse high voltage output is obtained through voltage doubling rectification; during the operation of the power supply, the primary side current, primary side voltage, secondary side voltage, and secondary side current are detected in real time, and the primary side current and voltage fault judgment module determines whether a primary fault occurs according to the detection signals of the primary side current and the primary side voltage. If so, the power supply is controlled to shut down and a fault alarm is issued. If not, the secondary side current and voltage fault judgment module determines whether a secondary fault occurs according to the detection signals of the secondary side voltage and the secondary side current. If so, the voltage regulating pulse control module reduces the duty cycle of the PWM signal to reduce the output voltage or the PWM lockout turns off the output of the IGBT drive signal, and no longer provides energy to the load. At the same time, a delay is entered, and the peak voltage output of the pulse high voltage generating circuit is reduced. After the delay, the normal PWM drive signal is started to generate, so that the power supply resumes work.

[0013] The specific method of the secondary side current and voltage fault judgment module to judge whether a secondary fault occurs according to the detection signals of the secondary side voltage and the secondary side current is as follows: (1) Determine whether the secondary current exceeds the set threshold. If so, it is judged as a fault. If not, proceed to the next step; (2) Determine whether the secondary voltage exceeds the set threshold. If so, it is determined to be a fault. If not, proceed to the next step. (3) Determine whether both the secondary current and the secondary voltage exceed the normal threshold. If so, it is determined to be a fault; Among them, the set threshold and the normal threshold are both set values, satisfying the following relationship; I2<I1, U2>U1, I1 represents the set threshold of the secondary current, U1 represents the set threshold of the secondary voltage, I2 represents the normal threshold of the secondary current, and U2 represents the normal threshold of the secondary voltage.

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention comprises a pulse high voltage generating circuit, a driving circuit and a control system; the pulse high voltage generating circuit comprises a primary filtering and rectifying module, a high frequency inverter circuit, a high frequency voltage transformer T and a voltage doubling rectifying circuit; the driving circuit is used to receive a PWM signal of a main control chip to drive the pulse high voltage generating circuit; based on the above-mentioned setting, the implementation method of the high frequency high voltage DC pulse power supply comprises a three-phase 380V input, a controllable rectification, a high frequency inverter and a ferrite transformer for boosting, and then a voltage doubling rectification to obtain a DC pulse high voltage output, the power supply operates stably, the pulse voltage is relatively high, and the application in environmental protection saves about 40% of electricity, and can be widely used in environmental protection equipment such as smoke removal, dust removal, odor removal, and moisture removal, with remarkable effect, stable quality and obvious power saving effect; on the other hand, the driving circuit is combined with the design of the control system, and in the process of power supply operation, the primary side current, the primary side voltage, the secondary side voltage and the secondary side current are detected in real time to judge whether a primary fault or a secondary fault occurs, and if so, the voltage regulating pulse control module reduces the duty cycle of the PWM signal to reduce the output voltage or the PWM The output of the IGBT drive signal is locked and shut down, and a delay is entered at the same time. After the delay, the normal PWM drive signal is started to resume work, providing better control and protection for the pulse power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the circuit principle of the pulse high voltage generating circuit in the present invention.

[0016] Figure 2 It is a schematic diagram of the circuit principle of the driving circuit in the present invention.

[0017] Figure 3 It is a principle block diagram of the control system in the present invention.

[0018] Figure 4 It is a control flow diagram of the present invention. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to have a clearer understanding and knowledge of the present invention, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described below are only used to explain the present invention, and are convenient for understanding. The technical solutions provided by the present invention are not limited to the technical solutions provided by the following embodiments, and the technical solutions provided by the embodiments should not limit the protection scope of the present invention.

[0020] Example like Figures 1 to 4 As shown, this embodiment provides a constant current high-frequency high-voltage DC pulse power supply for electrostatic dust removal, the pulse power supply includes a pulse high-voltage generating circuit, a driving circuit and a control system; the pulse high-voltage generating circuit includes a primary filter rectifier module, a high-frequency inverter circuit, a high-frequency voltage transformer T and a voltage doubling rectifier circuit; the above circuits constitute the main circuit, wherein the high-frequency voltage transformer T adopts a ferrite transformer, and the primary filter rectifier module adopts a three-phase controllable rectifier module MDS, which is made of six ultra-fast recovery diode chips and a high-power high-voltage thyristor chip connected according to a certain circuit and then packaged together in a PPS shell. Compared with the use of 3 to 5 ordinary rectifier diodes, the three-phase controlled rectifier module has a shorter reverse recovery time, which helps to reduce the electromagnetic interference of the inverter. Since the circuit connection has been completed inside the module, the wiring and symmetrical structure design are optimized, and the parasitic inductance and capacitance parameters of the device are reduced, which is conducive to the high frequency of the device. ‌‌

[0021] In this embodiment, the high-frequency inverter circuit adopts an H-bridge high-frequency inverter circuit, which includes four groups of IGBTs, namely Q1, Q2, Q3 and Q4, and a capacitor C1 is connected in parallel. It is controlled to be converted into an AC repetitive pulse with a repetition frequency of 100Hz. It is combined with capacitor C3, capacitor C2, and inductor L1 to form an LCC resonant converter, and the soft switching operation of the IGBT is realized through resonance.

[0022] The AC voltage is boosted by a high-frequency high-voltage transformer T, and then rectified by a voltage doubler rectifier circuit. In this embodiment, the voltage doubler rectifier circuit includes a diode D1, a diode D2, a capacitor C4, and a capacitor C5, and the diode is a high-voltage diode. The working principle of the voltage doubler rectifier circuit is as follows: in the first half cycle, the secondary side current flows from the upper end of the pulse transformer T through the high-voltage diode D1 and the capacitor C4 to the lower end of the transformer; in the second half cycle, the secondary side current flows from the lower end of the transformer through the capacitor C5 and the high-voltage diode D2 to the upper end of the transformer Tr.

[0023] In this embodiment, the IGBT in the H-bridge high-frequency inverter circuit is driven based on a driving circuit, and the driving circuit is used to receive the PWM signal of the main control chip to drive the pulse high voltage generating circuit; specifically, the driving circuit includes four IGBT driving circuits, and each driving circuit includes the following: a driving chip U1, pin 1 of the driving chip U1 is connected to the PWM pin of the main control MCU, pin 5 is connected to the REST pin of the main control MCU, pin 6 is connected to the FAULT pin of the main control MCU, pin 14 is connected to the IGBT collector via resistor R3 and diode D2, pin 11 is connected to the IGBT gate via resistor R6, and pin 16 is connected to the IGBT emitter; wherein, the driving chip adopts a gate drive optocoupler, model HCPL316J, which has the following characteristics: driving the IGBT, it can realize the "soft" shutdown of the IGBT, integrated anti-failure fault IGBT protection-desaturation VCE detection-undervoltage lockout protection (UVLO) with hysteresis, users can configure reverse, same direction, automatic reset, automatic shutdown, wide operating voltage range: 15V to 30V-40°℃ The MOSFET has a minimum common mode rejection (CMR) capability of 15 kVus at VCM = 1.500V over a wide temperature range from 100°C to 100°C, and has the advantages of higher resolution, better display contrast, and pin compatibility.

[0024] Based on the above settings, when the power supply is working, the three-phase 380V input is controlled rectified, then high-frequency inverted and boosted by a ferrite transformer, and then doubled rectified to obtain a DC pulse high-voltage output; the high-frequency pulse output high-voltage AC is then doubled and rectified, which saves 40% of electricity compared to traditional power frequency. In a further preferred solution, a self-feedback system can be set up to automatically increase or decrease the voltage according to the needs of discharge, and the required amount of electricity can be automatically given, which is more energy-saving than traditional constant power output.

[0025] The DC pulse power supply provided in this embodiment adopts three-phase power supply: ① The system power supply is balanced, which will not cause serious phase deviation of the power supply transformer, and the power factor is as high as 93% or more; ② The power supply voltage pulsation is small, the voltage average value is high, and the dust removal efficiency is extremely high; High-frequency pulse: The response speed of the system can be quickly increased from 50Hz to KH2-80KHz ultrasonic pulse drive signal, thereby improving the efficiency of capturing smoke dust.

[0026] In this embodiment, the control system includes a main control MCU, a signal sampling and processing module, a fault judgment module, a voltage regulation pulse control module, and a power supply; the voltage regulation pulse control module, when it is judged that a fault occurs, is used to reduce the duty cycle of the PWM signal and enter the delay at the same time, and reduce the peak voltage output of the pulse generating circuit. After the delay, the normal PWM drive signal is started. The above functional modules all communicate with the main control MCU, and the power supply is used for power supply.

[0027] In this embodiment, the main control chip of the main control MCU is dsPIC33AK128MC102, and its operating conditions are 3.0V to 3.6V: -40°C to +85'C, DC to 200 MHZ3.0V to 3.6V: -40°C to +150°C, DC to 200MHZ3.0V to 3.6V: -40°C to +125°C, DC to 200 MHZ; it has the following features: High-performance dsPIC33A digital signal controller (DSC) 32-bit rich instruction set to optimize speed and program code size: non-paged linear data flash 24-bit addressing space 16-bit / 32-bit instructions to optimize code size and performance 32-bit wide data path Single-precision and double-precision floating point unit (FPU) coprocessor / edge or level change notification interrupt on pin 0 Peripheral pin select (PPS) Remappable pins to reduce board layout complexity Multiple interrupt vectors with individually programmable priorities; Controller functions: High current sink / source input / output capability, programmable weak pull-up and pull-down resistors, programmable open-drain output Two 1.6 GHZ PLLs for peripherals, clocks can be provided by FRC or crystal oscillators, reference clock output (REFO), low power management mode (sleep and idle), reset and undervoltage reset. In this embodiment, the control functions implemented by the main control MCU are as follows (including but not limited to): (1) Convert analog signals such as voltage and current of the main circuit into digital signals, analyze the signals, determine whether there is a fault and the type of fault, and make corresponding protection control if there is a fault; (2) Generate corresponding IGBT drive waveforms to achieve corresponding voltage output and resonant soft switching.

[0028] In this embodiment, the signal sampling and processing module is used to sample and process: primary side current, primary side voltage, secondary side voltage, and secondary side current. It is implemented in combination with the corresponding signal sampling circuit, which is a conventional technical means and will not be elaborated here; the fault judgment module includes a primary side current and voltage fault judgment module and a secondary side current and voltage fault judgment module.

[0029] During the operation of the power supply, the primary side current, primary side voltage, secondary side voltage, and secondary side current are detected in real time. The primary side current and voltage fault judgment module determines whether a primary fault occurs according to the detection signals of the primary side current and the primary side voltage. If so, the power supply is controlled to shut down and a fault alarm is issued. This technical means can be implemented in combination with a relay. It belongs to conventional technical means, so it is not described here. If not, the secondary side current and voltage fault judgment module determines whether a secondary fault occurs according to the detection signals of the secondary side voltage and the secondary side current. Among them, the specific method for the secondary side current and voltage fault judgment module to determine whether a secondary fault occurs according to the detection signals of the secondary side voltage and the secondary side current is as follows: (1) Determine whether the secondary current exceeds the set threshold. If so, it is determined to be a fault. If not, proceed to the next step. Based on the set threshold, it is used to determine whether the secondary current has increased significantly. (2) Determine whether the secondary voltage exceeds the set threshold. If so, it is determined to be a fault. If not, proceed to the next step. Based on the set threshold, it is used to determine whether the secondary voltage has dropped significantly. (3) Determine whether both the secondary current and the secondary voltage exceed the conventional threshold. If so, it is determined to be a fault. Among them, the set threshold and the conventional threshold are both set values, and the following relationship is satisfied: I2<I1, U2>U1, I1 represents the set threshold of the secondary current, U1 represents the set threshold of the secondary voltage, I2 represents the conventional threshold of the secondary current, and U2 represents the conventional threshold of the secondary voltage.

[0030] If it is judged as a fault, the voltage regulating pulse control module reduces the duty cycle of the PWM signal, so that the output voltage decreases or the PWM lock turns off the output of the IGBT drive signal, and no longer provides energy to the load. At the same time, it enters the delay and reduces the peak voltage output of the pulse high voltage generation circuit. After the delay, the normal PWM drive signal is started to generate, so that the power supply resumes working. Through the above settings, the pulse power supply can be better controlled and protected.

[0031] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A constant current high frequency high voltage DC pulse power supply for electrostatic dust removal, characterized in that: It includes a pulse high voltage generating circuit, a driving circuit and a control system; the pulse high voltage generating circuit includes a primary filtering and rectifying module, a high frequency inverter circuit, a high frequency voltage transformer T and a voltage doubling rectifier circuit; the high frequency inverter circuit adopts an H-bridge high frequency inverter circuit, which is combined with a capacitor C3, a capacitor C2 and an inductor L1 to form an LCC resonant converter; the driving circuit is used to receive a PWM signal from a main control chip to drive the pulse high voltage generating circuit; the control system includes a main control MCU, a signal sampling and processing module, a fault judgment module, a voltage regulating pulse control module, and a power supply; the voltage regulating pulse control module, when it is judged that a fault occurs, is used to reduce the duty cycle of the PWM signal and enter a delay at the same time, and reduce the peak voltage output of the pulse generating circuit, and after the delay, start the normal PWM driving signal generation.

2. The constant current high frequency high voltage direct current pulse power supply for electrostatic precipitator according to claim 1, characterized in that: The main control chip of the main control MCU is dsPIC33AK128MC102; the primary filter rectifier module is a three-phase controllable rectifier module.

3. The constant current high frequency high voltage direct current pulse power supply for electrostatic precipitator according to claim 2, characterized in that: The H-bridge high-frequency inverter circuit includes four groups of IGBTs (Q1, Q2, Q3, Q4).

4. The constant current high frequency high voltage direct current pulse power supply for electrostatic precipitator according to claim 3, characterized in that: The drive circuit includes a four-way IGBT drive circuit, which includes a drive chip U1, wherein pin 1 of the drive chip U1 is connected to the PWM pin of the main control MCU, pin 5 is connected to the REST pin of the main control MCU, pin 6 is connected to the FAULT pin of the main control MCU, pin 14 is connected to the IGBT collector via resistor R3 and diode D2, pin 11 is connected to the IGBT gate via resistor R6, and pin 16 is connected to the IGBT emitter.

5. The constant current high frequency high voltage direct current pulse power supply for electrostatic precipitator according to claim 4, characterized in that: The voltage doubler rectifier circuit includes a diode D1, a diode D2, a capacitor C4, and a capacitor C5.

6. The constant current high frequency high voltage direct current pulse power supply for electrostatic precipitator according to claim 5, characterized in that: The high-frequency transformer T is a ferrite transformer.

7. The constant current high frequency high voltage direct current pulse power supply for electrostatic precipitator according to claim 6, characterized in that: The signal sampling and processing module is used to sample and process: primary side current, primary side voltage, secondary side voltage, and secondary side current.

8. The constant current high frequency high voltage direct current pulse power supply for electrostatic precipitator according to claim 7, characterized in that: The fault judgment module includes a primary side current and voltage fault judgment module and a secondary side current and voltage fault judgment module.

9. The method for realizing a constant current, high frequency, high voltage DC pulse power supply for electrostatic precipitator according to any one of claims 1 to 8, characterized in that: The three-phase 380V input is controlled rectified, then high-frequency inverted and boosted by a ferrite transformer, and then doubled rectified to obtain a DC pulse high-voltage output. During the operation of the power supply, the primary side current, primary side voltage, secondary side voltage and secondary side current are detected in real time. The primary side current and voltage fault judgment module determines whether a primary fault occurs based on the detection signals of the primary side current and the primary side voltage. If so, the power supply is controlled to shut down and a fault alarm is issued. If not, the secondary side current and voltage fault judgment module determines whether a secondary fault occurs based on the detection signals of the secondary side voltage and the secondary side current. If so, the voltage regulation pulse control module reduces the duty cycle of the PWM signal to reduce the output voltage or the PWM lock turns off the output of the IGBT drive signal, and no longer provides energy to the load. At the same time, it enters the delay and reduces the peak voltage output of the pulse high-voltage generating circuit. After the delay, the normal PWM drive signal is started to resume operation.

10. The method for realizing a constant current high frequency high voltage direct current pulse power supply for electrostatic precipitator according to claim 9, characterized in that: The specific method of the secondary side current and voltage fault judgment module to judge whether a secondary fault occurs according to the detection signals of the secondary side voltage and the secondary side current is as follows: (1) Determine whether the secondary current exceeds the set threshold. If so, it is judged as a fault. If not, proceed to the next step; (2) Determine whether the secondary voltage exceeds the set threshold. If so, it is determined to be a fault. If not, proceed to the next step. (3) Determine whether both the secondary current and the secondary voltage exceed the normal threshold. If so, it is determined to be a fault; Among them, the set threshold and the normal threshold are both set values, satisfying the following relationship; I2<I1, U2>U1, I1 represents the set threshold of the secondary current, U1 represents the set threshold of the secondary voltage, I2 represents the normal threshold of the secondary current, and U2 represents the normal threshold of the secondary voltage.

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