Method for spark intelligent control synchronous discharge of pulse power supply

Abstract

The present application provides a method for spark intelligent control synchronous discharge of pulse power supply, comprising the following steps: S1. Spark judgment stage: using multi-line sampling method, the secondary voltage average value and its slope, the secondary current average value and its slope are synchronously detected, and whether the spark appears is judged; S2. Spark processing stage: when step S1 judges that the spark appears, the secondary current is used to control the output of the secondary voltage, so that the secondary voltage is reduced to the nearest secondary voltage sampling value, rather than to 0, and the low voltage output is maintained; then the secondary current is controlled to recover to a lower value, and the secondary current gradually rises from the value according to the multi-section mode until the spark appears or reaches the set limit value, and then stabilizes, so that the spark processing is realized. The method can avoid the misjudgment of the spark, and improve the working efficiency of the equipment through the intelligent control of the spark.

Description

[Technical Field]

[0001] This invention relates to the technical field of suppressing back corona phenomena, and in particular to a method for intelligent control and synchronous discharge of sparks using a pulse power supply. [Background Technology]

[0002] Electrostatic precipitators are crucial dust removal equipment in power plants. Due to increasingly stringent environmental protection requirements, many power plants now use pulsed power supplies in their final electric fields. Pulsed power supplies increase the peak value of the secondary voltage while reducing corona current and suppressing back corona, thereby improving the dust removal efficiency of fine dust.

[0003] The voltage of a pulse power supply refers to the voltage generated by superimposing a momentary high voltage onto the base voltage. A stable output voltage from the pulse power supply is crucial for dust removal efficiency. Pulse voltages are particularly high (up to 150KV), easily generating sparks. These sparks severely affect the stability of the pulse power supply, necessitating effective spark control. Spark control methods consist of three steps: spark detection, spark handling, and spark monitoring.

[0004] a. Spark detection is mainly based on the instantaneous change slope of the secondary voltage or the extremely low secondary voltage value that persists for a long time (i.e., short circuit phenomenon).

[0005] b. Spark handling: Upon determining that there is a spark, immediately interrupt the primary side electrical circuit to make the secondary voltage output 0 and maintain it for several hundred microseconds.

[0006] c. Spark follow-up monitoring: After a spark is dealt with, the secondary voltage is gradually increased to the set value or the next spark judgment stage is entered.

[0007] Existing pulse power supplies suffer from two major drawbacks when sparks occur: outdated spark control technology and a lack of discharge protection measures for internal components. Firstly, the existing spark control technology is prone to misjudgment during the "spark detection" stage. This manifests in two ways: one, a spark actually occurs but cannot be accurately identified, leading to continuous power output and an increase in the number and size of sparks; two, no spark is actually detected but is mistakenly identified as a spark, resulting in spark suppression and reduced secondary-side output, thus lowering dust removal efficiency. The "spark suppression" stage is excessively long, during which there is no dust removal efficiency. Secondly, to prevent high-voltage breakdown of the pulse IGBT, pulse power supplies employ an electrical circuit consisting of absorption diodes, clamping resistors, and spark absorption capacitors. However, in actual operation, it has been found that when numerous sparks are generated locally in the electrostatic precipitator, and high voltage is input to the pulse power supply in reverse, the voltage across the spark absorption capacitor continuously rises, reaching up to 3000V. This makes the clamping resistor protecting the IGBT and the spark absorption capacitor prone to breakdown, as there is a lack of corresponding protective discharge circuit design at this point.

[0008] In summary, due to the inherent characteristics of pulsed power supplies, sparks can be particularly numerous and large under certain operating conditions, leading to severe fluctuations on the secondary side. Therefore, traditional flashover control methods frequently experience flashover misjudgments. Furthermore, continuous sparking can damage components in the reverse direction, increasing equipment failure rates and maintenance costs. [Summary of the Invention]

[0009] The purpose of this invention is to solve the problems in the prior art by proposing a method for intelligent control and synchronous discharge of sparks using a pulse power supply. This method can avoid misjudgment of sparks and improve the working efficiency of the equipment through intelligent control of sparks.

[0010] To achieve the above objectives, this invention proposes a method for intelligent control and synchronous discharge of sparks using a pulse power supply, comprising the following steps:

[0011] S1. Spark Detection Stage: Using multi-line sampling, the average value and slope of the secondary voltage and the average value and slope of the secondary current are simultaneously detected, and the following judgments are made:

[0012] a. The slope of the secondary voltage value is greater than its corresponding preset value, and the average value of the secondary voltage and the average value of the secondary current are less than their corresponding set values;

[0013] b. The slope of the secondary current value is greater than its corresponding preset value, and the average value of the secondary voltage and the average value of the secondary current are less than their corresponding set values;

[0014] A spark is considered to have occurred when either condition a or condition b is met, or both conditions are met simultaneously.

[0015] S2. Spark treatment stage: The secondary current is used to control the output of the secondary voltage, including the following steps:

[0016] S2.1 When step S1 determines that a spark has occurred, suppress the secondary current and reduce the secondary voltage to the most recent secondary voltage sampling value, rather than reducing it to 0, to maintain a low voltage output;

[0017] S2.2 Then control the secondary current to recover to a lower value, and from this value the secondary current gradually increases in a multi-segment mode;

[0018] S2.3 When the secondary current rises to the limit value at which sparks occur or reaches the set limit value, it stabilizes, thus achieving spark treatment.

[0019] Preferably, step S1 specifically includes the following steps:

[0020] S1.1 Sample the most recent consecutive secondary voltage values ​​at the power supply output terminal and calculate their slope, then proceed to step S1.2; simultaneously sample the most recent consecutive secondary current values ​​at the power supply output terminal and calculate their slope, then proceed to step S1.5.

[0021] S1.2 Compare the obtained secondary voltage slope with the set secondary voltage slope value; if it is greater than the set secondary voltage slope value, proceed to step S1.3; otherwise, return to S1.1.

[0022] S1.3 If the average value of the secondary voltage is less than the set secondary voltage value, proceed to step S1.4; otherwise, return to S1.1.

[0023] S1.4 If the average value of the secondary current is less than the set secondary current value, it is determined that a spark has occurred; otherwise, return to S1.1.

[0024] The secondary current slope obtained in S1.5 is compared with the set secondary current slope value; if it is greater than the set secondary current slope value, proceed to step S1.6; otherwise, return to S1.1.

[0025] S1.6 If the average value of the secondary current is less than the set secondary current value, proceed to step S1.7; otherwise, return to S1.1.

[0026] S1.7 If the average value of the secondary voltage is less than the set secondary voltage value, it is determined that a spark has occurred; otherwise, return to S1.1.

[0027] As a preferred method, the three most recent consecutive secondary voltage and secondary current values ​​at the power output terminal are simultaneously detected.

[0028] Preferably, in step S2.2, when the secondary current gradually increases in a multi-segment mode, the rising slope of the multi-segment mode increases sequentially.

[0029] Preferably, the method is implemented using a spark intelligent control system, which includes a sampling unit, an intelligent discharge control unit, and a discharge circuit. The sampling unit samples the voltage signal across the spark absorption capacitor in real time and transmits the signal to the intelligent discharge control unit. If the sampled voltage is higher than a set value, the discharge circuit is triggered to discharge instantaneously. Then, sampling and comparison are continuously performed until the voltage is lower than the set value.

[0030] The beneficial effects of this invention are as follows: The spark control method of this invention completely avoids misjudgment of sparks. Simultaneously, it does not suppress the output to zero during spark handling, improving equipment efficiency and ensuring the continuous operation of the dust collector. Furthermore, while ensuring spark control, the addition of a smart discharge design enhances the stability of various components and makes it more adaptable to harsh environments. This invention's proposed intelligent spark control and synchronous intelligent discharge significantly improves the reliability, adaptability, and stability of the equipment.

[0031] The features and advantages of the present invention will be described in detail through embodiments and in conjunction with the accompanying drawings. [Attached Image Description]

[0032] Figure 1 This is a flowchart of the spark determination stage in this invention;

[0033] Figure 2 This is a schematic diagram of the spark processing stage in this invention;

[0034] Figure 3 This is the processing flowchart of the Spark Intelligent Control System;

[0035] Figure 4 This is a schematic diagram showing the installation location of the spark absorption capacitor in the pulse power supply.

[0036] Figure 5 This is the electrical circuit diagram for a spark absorber capacitor;

[0037] Figure 6 This is the electrical circuit diagram of the discharge circuit of the Spark Intelligent Control System.

Detailed Implementation Methods

[0038] This invention discloses a method for intelligent control and synchronous discharge of sparks using a pulse power supply, comprising the following steps:

[0039] S1. Spark Detection Stage: Multi-line sampling is employed to improve reliability. The average value and slope of the secondary voltage and the average value and slope of the secondary current are simultaneously detected, and the following judgments are made:

[0040] a. The slope of the secondary voltage value is greater than its corresponding preset value, and the average value of the secondary voltage and the average value of the secondary current are less than their corresponding set values;

[0041] b. The slope of the secondary current value is greater than its corresponding preset value, and the average value of the secondary voltage and the average value of the secondary current are less than their corresponding set values;

[0042] A spark is considered to have occurred when either condition a or condition b is met, or both conditions are met simultaneously.

[0043] S2. Spark Testing Stage: Since the power supply is a current source, secondary current is used to control the output of the secondary voltage, including the following steps:

[0044] See S2.1 Figure 2 When step S1 determines that a spark has occurred (point a), the secondary current is suppressed (point b), and the secondary voltage is reduced to the most recent secondary voltage sampling value, rather than reduced to 0, to maintain a low voltage output.

[0045] S2.2 Then control the secondary current to recover to a lower value (point c). From this value (point c), the secondary current gradually increases in a multi-segment mode. In this embodiment, it gradually increases in segments A, B, and C, and the rising slope of the multi-segment mode increases sequentially. The secondary current continues to rise for a period of time B, and then the curve will rise along segment C with a certain slope. The current step size and the slope of segments A, B, and C can all be adjusted.

[0046] S2.3 When the secondary current rises to the limit value at which sparks occur or reaches the set limit value, it stabilizes, thus achieving spark treatment.

[0047] Further, see Figure 1 Step S1 specifically includes the following steps:

[0048] S1.1 Sample the most recent consecutive secondary voltage values ​​at the power output terminal and calculate their slope, then proceed to step S1.2; Simultaneously sample the most recent consecutive secondary current values ​​at the power output terminal and calculate their slope, then proceed to step S1.5. In this embodiment, the most recent three consecutive secondary voltage values ​​and secondary current values ​​at the power output terminal are sampled synchronously.

[0049] S1.2 Compare the obtained secondary voltage slope with the set secondary voltage slope value; if it is greater than the set secondary voltage slope value, proceed to step S1.3; otherwise, return to S1.1.

[0050] S1.3 If the average value of the secondary voltage is less than the set secondary voltage value, proceed to step S1.4; otherwise, return to S1.1.

[0051] S1.4 If the average value of the secondary current is less than the set secondary current value, it is determined that a spark has occurred; otherwise, return to S1.1.

[0052] The secondary current slope obtained in S1.5 is compared with the set secondary current slope value; if it is greater than the set secondary current slope value, proceed to step S1.6; otherwise, return to S1.1.

[0053] S1.6 If the average value of the secondary current is less than the set secondary current value, proceed to step S1.7; otherwise, return to S1.1.

[0054] S1.7 If the average value of the secondary voltage is less than the set secondary voltage value, it is determined that a spark has occurred; otherwise, return to S1.1.

[0055] Furthermore, the intelligent discharge design addresses the issue that even after spark detection and suppression, the power supply components still carry high voltage, posing a risk of high-voltage breakdown. Since the high voltage cannot be released instantaneously, a spark intelligent control system is proposed to protect components from instantaneous discharge. This system achieves intelligent spark control and intelligent discharge simultaneously, ensuring stable operation of the components within the cabinet. In this embodiment, the spark intelligent control system includes a sampling unit, an intelligent discharge control unit, and a discharge circuit; as... Figure 3 As shown, the spark absorption capacitance (e.g., ...) is sampled in real time by the sampling unit. Figure 4 As shown: Four capacitors connected in parallel; the location of the electrical circuit diagram for the spark absorber capacitor is shown below. Figure 5 The voltage signal at both ends (as shown) is transmitted to the intelligent discharge control unit. If the sampled voltage is higher than the set value, the discharge circuit is triggered to discharge instantaneously. Then, sampling and comparison are continuously performed until the voltage falls below the set value. The entire process achieves intelligent discharge of the spark. The electrical principle is as follows: Figure 6 The newly added intelligent discharge circuit may involve dozens or even hundreds of sparks per minute, achieving precise intelligent discharge. Moreover, the electrical circuit can still operate stably for a long time even when frequently triggered (at least more than the number of sparks).

[0056] See Figure 5 In the pulse generation circuit, the charging voltage from the front stage first charges the energy storage capacitors (C9, C10). When the IGBTs (V1, V2) are closed, a resonant circuit is formed by the energy storage capacitors (C9, C10), pulse transformers (T1, T2), high-voltage coupling capacitor (C11), and the equivalent capacitance of the dust collector. The initial voltage across the energy storage capacitors (C9, C10) generates a series resonance, ultimately producing a pulse voltage waveform across the dust collector. When the resonance reaches the point where the current reverses, the IGBTs (V1, V2) are disconnected, and the anti-parallel diodes of the IGBTs (V1, V2) provide freewheeling current, completing a full series resonant cycle. In this pulse generation circuit, clamping resistors (R1, R5), clamping diodes (D7, D11), and spark absorption capacitors (C1, C5) form a circuit to protect the IGBTs (V1, V2) from overvoltage. However, in actual operation, it was found that, especially when there are many sparks in the electric field body, the protection circuit cannot meet the requirements normally. The voltage across the IGBT will continue to rise, causing tripping or even damaging the diodes in the protection circuit.

[0057] against Figure 5 The main circuit adopts Figure 6An electrical circuit is used to achieve instantaneous discharge, ensuring that the pulse power supply can still operate normally under complex high-spark conditions. Based on Figure 4 The structure, Figure 5 Based on the principle of the electrical circuit, it is convenient to install and maintain, and can intelligently discharge instantaneously. Therefore, a new circuit is added across the spark absorption capacitor (C1). Figure 6 The electrical circuit. Since the IGBT high voltage is transmitted from the secondary side, only a discharge circuit needs to be added for C1; there is no need to add one for C5. For example... Figure 6 As shown, the spark absorption capacitor (C1) is connected to a "voltage sampling board" to sample a high-voltage signal (1500VDC to 3000VDC) and transmit it as a 0-5VDC signal to the "intelligent discharge board". The "intelligent discharge board" has a set discharge voltage, which is compared with the sampled 0-5V. When the set value is higher than the sampled value, the intelligent discharge board instantly outputs a signal (24VDC) to activate the relay KM1. This activates the resistor R1 circuit, causing an instantaneous discharge, which instantly reduces the voltage across the spark absorption capacitor (C1), thus realizing the intelligent discharge protection function of the IGBT voltage.

[0058] The above embodiments are illustrative of the present invention and are not intended to limit the present invention. Any simple modifications to the present invention are within the scope of protection of the present invention.

Claims

1. A method for spark intelligent control synchronous discharge of pulse power supply, characterized in that: The method comprises the following steps: S1. Spark judgment stage: using multi-line sampling method, the secondary voltage average value and its slope, the secondary current average value and its slope are detected synchronously, and the following judgments are made: a. The slope of the secondary voltage value is greater than the corresponding preset value, and the secondary voltage average value and the secondary current average value are less than the corresponding set value; b. The slope of the secondary current value is greater than the corresponding preset value, and the secondary voltage average value and the secondary current average value are less than the corresponding set value; When any one of conditions a and b is met or both conditions are met, it is judged that a spark occurs; S2. Spark processing stage: using the secondary current to control the output of the secondary voltage, comprising the following steps: S2.1 When it is judged in step S1 that a spark occurs, the secondary current is suppressed, the secondary voltage is reduced to the latest secondary voltage sampling value, not to 0, and a low-voltage output is maintained; S2.2 Then control the secondary current to recover to a lower value, and the secondary current gradually rises from this value according to a multi-section mode; S2.3 When the secondary current rises to the limit value of the occurrence of the spark or reaches the set limit value and stabilizes, the spark processing is realized.

2. The method for spark intelligent control synchronous discharge of a pulse power supply according to claim 1, characterized in that: Step S1 specifically comprises the following steps: S1.1 Sample the latest continuous multiple secondary voltage values at the output end of the power supply and calculate the slope, then enter step S1.2; at the same time, sample the latest continuous multiple secondary current values at the output end of the power supply and calculate the slope, then enter step S1.5; S1.2 Compare the obtained secondary voltage slope with the set secondary voltage slope value; if it is greater than the set secondary voltage slope value, enter step S1.3; otherwise, return to S1.1; S1.3 If the secondary voltage average value is less than the set secondary voltage value, enter step S1.4; otherwise, return to S1.1; S1.4 If the secondary current average value is less than the set secondary current value, it is judged that a spark occurs; otherwise, return to S1.1; S1.5 Compare the obtained secondary current slope with the set secondary current slope value; if it is greater than the set secondary current slope value, enter step S1.6; otherwise, return to S1.1; S1.6 If the secondary current average value is less than the set secondary current value, enter step S1.7; otherwise, return to S1.1; S1.7 If the secondary voltage average value is less than the set secondary voltage value, it is judged that a spark occurs; otherwise, return to S1.

1.

3. The method for spark intelligent control synchronous discharge of a pulse power source according to claim 1 or 2, characterized in that: The latest continuous three secondary voltage values and secondary current values at the output end of the power supply are synchronously detected.

4. The method for controlling the synchronization of the discharge of a spark by the pulse power source according to claim 1, characterized in that: When the secondary current gradually rises according to the multi-section mode in step S2.2, the rising slopes of the multi-section mode increase in turn.

5. The method for controlling the synchronization of the discharge of a spark by the pulse power source according to claim 1, characterized in that: The method is realized by using a spark intelligent control system, the spark intelligent control system comprises a sampling unit, an intelligent discharge control unit and a discharge circuit; the voltage signal between the two ends of the spark absorption capacitor is sampled in real time by the sampling unit, and the signal is transmitted to the intelligent discharge control unit; if the sampled voltage is higher than the set value, the discharge circuit is triggered to discharge instantaneously, and then sampling and comparison are continuously performed until the voltage is lower than the set value.

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