A high frequency power supply control method, system and power supply device for dust removal

Abstract

The present invention provides a high-frequency power supply control method, system and power supply equipment for dust removal, the power supply equipment includes: a rectifier, an inverter, a transformer and a sampling board, a controller, three-phase alternating current is output to a load through the rectifier, the inverter and the transformer, the controller receives the electrical signals of the secondary voltage and the secondary current on the sampling board and controls the circuit, the method includes: sampling and obtaining the secondary voltage and the secondary current; judging whether the short-circuit condition is met, if so, controlling the tripping and reporting the short-circuit fault; if not, continuing to judge whether the preset condition one is met, if so, outputting a quasi-short-circuit alarm and tripping; if not, continuing to judge whether the preset condition two is met; if so, outputting a quasi-short-circuit alarm and tripping; if not, operating normally. Under the condition of being close to a short circuit, the controller controls the switch through the sampling signal logic judgment program, avoiding the influence of the arc high temperature generated by the short circuit on the power supply equipment, and improving the safety and reliability of the power supply equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of electrostatic precipitator, and in particular to a high-frequency power supply control method, system and power supply equipment for dust removal. Background Art

[0002] Arcing is a gas discharge phenomenon, an instantaneous spark generated by current passing through certain insulating media (such as air). The arc is a high-temperature, high-conductivity free gas, which not only has a great destructive effect on the contacts, but also prolongs the time to disconnect the circuit. The arc generally bypasses the insulator and is generated along the surface of the insulator, thus causing damage to the insulator. For example, the high temperature of the arc can cause the insulator to melt or break. For example, if the rated short-circuit breaking current on the switch is 20KA, it means that the short-circuit trip contact arc extinguishing thermal element action within 20KA is effective. If it exceeds this limit, the arc extinguishing thermal element action of the trip contact is not guaranteed, and arcing will occur.

[0003] The operating conditions of the electrostatic precipitator are complex and varied. The biggest cause of arcing is a problem with the spark detection circuit. When the spark is out of control because it is not detected, it will transition to arcing. At this time, the current limit and voltage limit are still in effect, the secondary current limit operates below the setting, and the secondary voltage is at a small value due to dielectric breakdown. When the equipment operates in this state, the voltage is low and the secondary current is controlled. It may not be very destructive to the high-frequency power supply itself, but it will damage the electric field and may cause breakdown and damage to the electric field plate. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a high-frequency power supply equipment, control method and system for dust removal, which can solve the damage of power supply equipment caused by arcing in the prior art. By starting the control program to control alarm and tripping when a short circuit is approaching, the power supply equipment can be better protected, making the power supply equipment safer and more reliable.

[0005] One of the present inventions is implemented as follows: a method for controlling a high-frequency power supply for dust removal, comprising the following steps:

[0006] S1, sampling to obtain the secondary voltage and secondary current of the main circuit;

[0007] S2, judging whether the secondary voltage and secondary current meet the short-circuit condition,

[0008] S3, if yes, then the control trips and exits the program;

[0009] S4, if not, determine whether it meets the preset condition 1,

[0010] If S41 meets the requirements, start timing and enter the first timing control program;

[0011] If S42 does not meet the requirement, the timer is reset to zero to determine whether the preset condition 2 is met.

[0012] If S43 meets the requirements, the timing starts and the second timing control program is entered;

[0013] If S44 does not meet the requirements, the timer will be reset, the equipment will operate normally, and the program will exit.

[0014] Preferably, the preset condition 1 in step S4 includes:

[0015] The secondary voltage and the secondary current are detected to determine whether they meet the requirements of strong arc pulling. The determination conditions of strong arc pulling are: the secondary current is greater than 50% of the rated current, and the secondary voltage is less than the first set voltage.

[0016] Preferably, the step S41 enters the first timing control procedure, including:

[0017] Start calculating the duration of the strong arc pulling. If the duration of the strong arc pulling is less than the first limited time, the device operates normally and exits the program.

[0018] If the duration of the strong arc is greater than or equal to the first limited time, the control program is reset once. If the number of resets within 1 hour is less than or equal to the limited number, the number of resets is accumulated, the device operates normally, and the program is exited;

[0019] If the number of resets within 1 hour is greater than the specified number, a quasi-short-circuit alarm will be output, the circuit breaker will be controlled, and the program will be exited.

[0020] Preferably, the second preset condition in step S42 includes:

[0021] The secondary voltage and the secondary current are detected to determine whether they meet the requirements of weak arcing. The determination conditions of weak arcing are: the secondary current is greater than the first set current and less than 50% of the rated current, and the secondary voltage is less than the first set voltage.

[0022] Preferably, the step S43 enters the second timing control procedure, including:

[0023] Start calculating the duration of weak arc pulling. If the duration of weak arc pulling is less than the second limited time, the device operates normally and exits the program.

[0024] If the duration of the weak arc is greater than or equal to the second limited time, a quasi-short circuit alarm is output and the circuit breaker is tripped.

[0025] Preferably, the short circuit judgment condition is: the secondary current is greater than the second set current, and the secondary voltage is less than the second set voltage, and the duration is the set fault time.

[0026] The second aspect of the present invention is implemented as follows: a control system for a high-frequency power supply for dust removal, characterized in that it includes the following modules:

[0027] Sampling module, sampling and obtaining the secondary voltage and secondary current of the main circuit;

[0028] A judgment control module is used to judge whether the secondary voltage and secondary current obtained by the sampling module meet the short-circuit condition.

[0029] If yes, the control trips and exits the program. If no, determine whether the strong arc pulling conditions are met:

[0030] If it meets the requirements, the control program starts timing. If the duration of the strong arc is less than the first limited time, the program will be exited, the equipment will operate normally, and the program will be exited; if the duration of the strong arc is greater than or equal to the first limited time, it will be reset once. If the number of resets within 1 hour is less than or equal to the limited number, the number of resets will be accumulated; if the number of resets within 1 hour is greater than the limited number, a quasi-short circuit alarm will be output, and the control will trip, and the program will be exited;

[0031] If not, the control program will reset the timer to zero and determine whether the weak arc condition is met:

[0032] If it meets the requirements, the control program starts timing. If the duration of the weak arc is less than or equal to the second limited time, the device will operate normally and exit the program. If the duration of the weak arc is greater than the second limited time, a quasi-short circuit alarm will be output and the circuit breaker will be tripped.

[0033] If it does not meet the requirements, the weak arc timing will be reset to zero, the equipment will operate normally, and the program will be exited;

[0034] The program module is a functional medium used to store computer programs and realize the functions of the judgment control module.

[0035] Preferably, the judgment condition of the strong arc pulling is: the secondary current is greater than 50% of the rated current, and the secondary voltage is less than the first set voltage;

[0036] The judgment conditions for weak arcing are: the secondary current is greater than the first set current and less than 50% of the rated current, and the secondary voltage is less than the first set voltage;

[0037] The short circuit judgment conditions are: the secondary current is greater than the second set current, and the secondary voltage is less than the second set voltage, and the duration is the set fault time.

[0038] The third aspect of the present invention is achieved as follows: a power supply device, comprising:

[0039] A rectifier, wherein the input end of the rectifier is the input end of the power supply device;

[0040] An inverter, wherein an input end of the inverter is connected to an output end of the rectifier;

[0041] A transformer, wherein an input end of the transformer is connected to an output end of the inverter, and an output end of the transformer is connected to a load;

[0042] A sampling board, wherein the input end of the sampling board is connected to the output end of the transformer and is used for sampling secondary voltage and secondary current signals;

[0043] A controller, wherein an input end of the controller is connected to an output end of the sampling board, and an output end of the controller is connected to an input end of the inverter;

[0044] The three-phase AC power is output to the load through the rectifier, the inverter and the transformer, and the controller receives the secondary voltage and secondary current electrical signals collected by the sampling board and uses them to control the equipment;

[0045] The secondary voltage and secondary current signals are obtained by a high-frequency power supply control method for dust removal.

[0046] Compared with the prior art, the present invention has the following advantages: after the high-frequency power supply enters the working state, it is determined whether it enters the near short circuit (i.e., quasi-short circuit) working state by sampling the secondary voltage and secondary current signals. When the secondary voltage and secondary current meet the quasi-short circuit working state, the timing control module starts timing, the strong arcing lasts for more than 1 second, the program is reset once, and two strong arcing resets are detected within one hour. The main control program outputs a quasi-short circuit tripping fault and controls the tripping; if the weak arcing lasts for more than 1 minute, the main control program outputs a quasi-short circuit tripping fault and controls the tripping; under the condition of near short circuit, the controller controls the tripping through signal logic judgment, thereby avoiding the influence of the high temperature of the arc generated by the short circuit on the power supply equipment and improving the safety and reliability of the power supply equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The present invention will be further described below in conjunction with embodiments with reference to the accompanying drawings.

[0048] Figure 1 A flowchart of the method execution provided in an embodiment of the present invention.

[0049] Figure 2 Another method execution flow chart provided for an embodiment of the present invention.

[0050] Figure 3 A schematic diagram of the system structure provided by an embodiment of the present invention.

[0051] Figure 4 A schematic diagram of the structure of a power supply device provided in an embodiment of the present invention.

[0052] In the figure: 100, sampling module; 200, judgment control module; 300, program module; 401, rectifier; 402, inverter; 403, transformer; 404, sampling board; 405, controller. DETAILED DESCRIPTION

[0053] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0054] The most critical concept of the present invention is: the secondary voltage and secondary current on the main circuit are sampled by a sampling board, and sent to the single-chip microcomputer control program through the analog input of the main board. The single-chip microcomputer control program runs to determine whether the secondary voltage and secondary current meet the preset conditions. If so, the main control program unit is turned on, a quasi-short-circuit alarm is output, and the circuit breaker is tripped and shut down to perform internal detection of the electric field.

[0055] Generally speaking, we define the situation where the power supply equipment is close to short circuit as quasi short circuit. Quasi short circuit is divided into two control modes, including strong arc pulling and weak arc pulling.

[0056] Judgment conditions for strong arc pulling: secondary current is greater than 50% of rated current, and secondary voltage is less than 20kV;

[0057] Weak arcing judgment conditions: secondary current is greater than 100mA and less than 50% of rated current, and secondary voltage is less than 20kV;

[0058] The short circuit judgment conditions are: the secondary current is greater than 200mA and the secondary voltage is less than 8kV;

[0059] If the short circuit judgment condition lasts for 1 second, it is considered a short circuit.

[0060] The working conditions on site vary, and most of them will meet the short-circuit judgment conditions. Therefore, the high-frequency equipment on site is currently classified as short-circuit protection in these cases; however, when the equipment works in the arcing state with a secondary voltage greater than 8kV and less than 20kV, there is no protection measure. We define this phenomenon as quasi-short circuit.

[0061] The capacity range of high-frequency power supply is U2 (66KV-88KV), I2 (300mA-1800mA). The following parameters take the commonly used capacity (72KV, 1000mA) as an example.

[0062]

[0063] In view of the above analysis, we add quasi-short-circuit control logic to the high-frequency control program.

[0064] The present invention divides quasi-short circuit into strong arc and weak arc.

[0065] Arcing is very harmful to the electric field itself and will burn through and damage the plates. Therefore, when the main control program detects this high-energy and highly harmful working condition, the main control program first determines whether the short-circuit conditions are met. If the short-circuit conditions are met, the operation is immediately terminated and a short-circuit fault is reported.

[0066] If the short-circuit condition is not met, the main control program determines whether it meets the strong arc condition. If it meets the strong arc condition, the strong arc timing is accumulated. If the strong arc time is less than 1 second, the program returns to normal operation. If the strong arc time exceeds 1 second, the main control program will actively reset once. If the number of resets does not exceed two times within one hour, the number of active resets of the program will be accumulated; if the number of resets exceeds two times within one hour, the main control program will output a quasi-short-circuit alarm and trip, waiting for on-site staff to check and handle.

[0067] If the short-circuit condition is not met, the main control program determines whether the strong arc condition is met. If the strong arc condition is not met, the strong arc timing is reset to zero. It determines whether the weak arc condition is met. If the weak arc condition is not met, the weak arc timing is reset to zero. If the weak arc condition is met, the weak arc timing is accumulated. If the weak arc timing is less than 1 minute, the program returns to normal operation. If the weak arc timing exceeds 1 minute, the main control program outputs a quasi-short-circuit alarm and trips, waiting for on-site staff to check and handle.

[0068] like Figure 1-2 As shown, an embodiment of the present invention provides a method for controlling a high-frequency power supply for dust removal, comprising the following steps:

[0069] S1, sampling to obtain the secondary voltage and secondary current of the main circuit;

[0070] S2, judging whether the secondary voltage and secondary current meet the short-circuit condition,

[0071] S3, if yes, then the control trips and exits the program;

[0072] S4, if not, determine whether it meets the preset condition 1,

[0073] If S41 meets the requirements, start timing and enter the first timing control program;

[0074] If S42 does not meet the requirement, the timer is reset to zero to determine whether the preset condition 2 is met.

[0075] If S43 meets the requirements, the timing starts and the second timing control program is entered;

[0076] If S44 does not meet the requirements, the timer will be reset, the equipment will operate normally, and the program will exit.

[0077] Furthermore, the preset condition 1 in step S4 includes:

[0078] Detect and determine whether the secondary voltage and secondary current meet the strong arc pulling conditions. The judgment conditions for strong arc pulling are: the secondary current is greater than 50% of the rated current, and the secondary voltage is less than the first set voltage, and the first limit voltage is 20kV.

[0079] Furthermore, the step S41 enters the first timing control procedure, including:

[0080] Start calculating the duration of the strong arc pulling. If the duration of the strong arc pulling is less than the first limited time, the device operates normally and exits the program.

[0081] If the duration of the strong arc is greater than or equal to the first limited time, the control program is reset once. If the number of resets within 1 hour is less than or equal to the limited number, the number of resets is accumulated, the device operates normally, and the program is exited;

[0082] If the number of resets within 1 hour is greater than the specified number, a quasi-short-circuit alarm will be output and the circuit breaker will be tripped.

[0083] Furthermore, the first limited time is 1 second, and the limited number of times is 2 times.

[0084] Furthermore, the second preset condition in step S42 includes:

[0085] Detect and determine whether the secondary voltage and secondary current meet the requirements of weak arcing. The judgment conditions for weak arcing are: the secondary current is greater than the first set current and less than 50% of the rated current, and the secondary voltage is less than the first set voltage. The first set current is 100mA.

[0086] Furthermore, the step S43 enters the second timing control procedure, including:

[0087] Start calculating the duration of weak arc pulling. If the duration of weak arc pulling is less than the second limited time, the device operates normally and exits the program.

[0088] If the duration of the weak arc is greater than or equal to the second limited time, a quasi-short circuit alarm is output and the circuit breaker is tripped;

[0089] The second limited time is 1 minute.

[0090] Furthermore, the short circuit judgment condition is: the secondary current is greater than the second set current, and the secondary voltage is less than the second set voltage, and the duration is the set fault time;

[0091] The second set current is 200mA.

[0092] In the embodiment of the present invention, secondary voltage and secondary current signals are obtained by sampling, and program logic is used to determine whether quasi-short circuit conditions are met, so that tripping is controlled and a short circuit alarm is output, thereby reducing the risk of equipment damage due to short circuit.

[0093] like Figure 3 The embodiment of the present invention provides a control system for a high-frequency power supply for dust removal, comprising the following modules:

[0094] The sampling module 100 samples and obtains the secondary voltage and secondary current of the main circuit;

[0095] The judgment control module 200 judges whether the secondary voltage and secondary current obtained by the sampling module meet the short-circuit condition.

[0096] If yes, the control trips and exits the program. If no, determine whether the strong arc pulling conditions are met:

[0097] If it meets the requirements, the control program starts timing. If the duration of the strong arc is less than the first limited time, the device will run normally and exit the program. If the duration of the strong arc is greater than or equal to the first limited time, it will be reset once. If the number of resets within 1 hour is less than or equal to the limited number, the number of resets will be accumulated. If the number of resets within 1 hour is greater than the limited number, a quasi-short circuit alarm will be output and the circuit breaker will be controlled to trip.

[0098] If not, the control program will reset the timer to zero and determine whether the weak arc condition is met:

[0099] If it meets the requirements, the control program starts timing. If the duration of the weak arc is less than or equal to the second limited time, the device will operate normally and exit the program. If the duration of the weak arc is greater than the second limited time, a quasi-short circuit alarm will be output and the circuit breaker will be tripped.

[0100] If it does not meet the requirements, the weak arc timing will be reset to zero, the equipment will operate normally, and the program will be exited;

[0101] The program module 300 is a functional medium for storing computer programs to implement the functions of the judgment control module.

[0102] Furthermore, the judgment condition of the strong arc pulling is: the secondary current is greater than 50% of the rated current, and the secondary voltage is less than the first set voltage;

[0103] The judgment conditions for weak arcing are: the secondary current is greater than the first set current and less than 50% of the rated current, and the secondary voltage is less than the first set voltage;

[0104] The short circuit judgment conditions are: the secondary current is greater than the second set current, and the secondary voltage is less than the second set voltage, and the duration is the set fault time.

[0105] Furthermore, the first limited time is 1 second, the limited number of times is 2 times, the second limited time is 1 minute, the first set voltage is 20kV, the second set voltage is 8kV, the first set current is 100mA, and the second set current is 200mA.

[0106] like Figure 4 , a power supply device provided by an embodiment of the present invention includes:

[0107] A rectifier 401, wherein the input end of the rectifier 401 is the input end of the power supply device;

[0108] An inverter 402, wherein an input end of the inverter 402 is connected to an output end of the rectifier;

[0109] A transformer 403, wherein an input end of the transformer 403 is connected to an output end of the inverter, and an output end of the transformer 403 is connected to a load;

[0110] A sampling board 404, wherein the input end of the sampling board 404 is connected to the output end of the transformer 403, and is used to sample secondary voltage and secondary current signals;

[0111] A controller 405, wherein the input end of the controller 405 is connected to the output end of the sampling board 404, the output end of the controller 405 is connected to the output end of the rectifier 401, and the output end of the controller 405 is connected to the input end of the inverter;

[0112] The three-phase AC power is output to the load through the rectifier, the inverter and the transformer, and the controller receives the secondary voltage and secondary current electrical signals collected by the sampling board and uses them to control the equipment;

[0113] The secondary voltage and secondary current signals are obtained by sampling the sampling board.

[0114] Although the specific implementation modes of the present invention are described above, those skilled in the art should understand that the specific implementation modes described are only illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for controlling a high frequency power supply for dust removal, characterized in that , including the following steps: S1, sampling to obtain the secondary voltage and secondary current of the main circuit; S2, judging whether the secondary voltage and secondary current meet the short-circuit condition: S3, if yes, then the control trips and exits the program; S4, if not, determine whether the preset condition 1 is met, the preset condition 1 includes: detecting and determining whether the secondary voltage and the secondary current meet the requirements of strong arc pulling, the judgment condition of strong arc pulling is: the secondary current is greater than 50% of the rated current, and the secondary voltage is less than the first set voltage; S41, if it meets the conditions, start timing and enter the first timing control program; S42, if not, the timer is reset to zero and it is determined whether the preset condition 2 is met, wherein the preset condition 2 includes: detecting and determining whether the secondary voltage and the secondary current meet the weak arcing condition, and the weak arcing condition is: the secondary current is greater than the first set current and less than 50% of the rated current, and the secondary voltage is less than the first set voltage; S43, if it meets the conditions, start timing and enter the second timing control program; S44, if it does not meet the requirements, the timer is reset, the equipment runs normally, and the program exits.

2. The method for controlling a high-frequency power supply for dust removal according to claim 1, characterized in that: The step S41 enters the first timing control procedure, including: Start calculating the duration of the strong arc pulling. If the duration of the strong arc pulling is less than the first limited time, the device operates normally and exits the program. If the duration of the strong arc is greater than or equal to the first limited time, the control program is reset once. If the number of resets within 1 hour is less than or equal to the limited number, the number of resets is accumulated, the device operates normally, and the program is exited; If the number of resets within 1 hour is greater than the specified number, a quasi-short-circuit alarm will be output, the circuit breaker will be controlled, and the program will be exited.

3. The method for controlling a high-frequency power supply for dust removal according to claim 1, characterized in that: The step S43 enters the second timing control procedure, including: Start calculating the duration of weak arc pulling. If the duration of weak arc pulling is less than the second limited time, the device operates normally and exits the program. If the duration of the weak arc is greater than or equal to the second limited time, a quasi-short circuit alarm is output, and the circuit breaker is controlled to trip and exit the program.

4. The method for controlling a high-frequency power supply for dust removal according to claim 1, characterized in that: The short circuit judgment condition is: the secondary current is greater than the second set current, and the secondary voltage is less than the second set voltage, and the duration is the set fault time.

5. A control system for implementing the control method of the high-frequency power supply for dust removal according to claim 1, characterized in that: Includes the following modules: Sampling module, sampling and obtaining the secondary voltage and secondary current of the main circuit; A judgment control module is used to judge whether the secondary voltage and secondary current obtained by the sampling module meet the short-circuit condition. If yes, the control trips and exits the program. If no, determine whether the strong arc pulling conditions are met: If it meets the requirements, the first timing control program starts timing. If the duration of the strong arc is less than the first limited time, the equipment will run normally and exit the program; if the duration of the strong arc is greater than or equal to the first limited time, it will be reset once. If the number of resets within 1 hour is less than or equal to the limited number, the number of resets will be accumulated; if the number of resets within 1 hour is greater than the limited number, a quasi-short circuit alarm will be output, and the circuit breaker will be controlled to trip and exit the program; If not, reset the timer to zero to determine whether the weak arc condition is met: If it meets the requirements, the second timing control program starts timing. If the duration of the weak arc is less than or equal to the second limited time, the device will operate normally and exit the program. If the duration of the weak arc is greater than the second limited time, a quasi-short circuit alarm will be output, and the circuit breaker will be tripped and the program will exit. If it does not meet the requirements, the timer will be reset to zero, the device will operate normally, and the program will be exited; The program module is a functional medium used to store computer programs and realize the functions of the judgment control module.

6. A control system according to claim 5, characterized in that: The judgment condition of the strong arc pulling is: the secondary current is greater than 50% of the rated current, and the secondary voltage is less than the first set voltage; The judgment conditions for weak arcing are: the secondary current is greater than the first set current and less than 50% of the rated current, and the secondary voltage is less than the first set voltage; The short circuit judgment condition is: the secondary current is greater than the second set current, and the secondary voltage is less than the second set voltage, and the duration is the set fault time.

7. A power supply device for implementing the control method of the high-frequency power supply for dust removal according to claim 1, characterized in that: include: A rectifier, wherein the input end of the rectifier is the input end of the power supply device; An inverter, wherein an input end of the inverter is connected to an output end of the rectifier; A transformer, wherein an input end of the transformer is connected to an output end of the inverter, and an output end of the transformer is connected to a load; A sampling board, wherein the input end of the sampling board is connected to the output end of the transformer and is used for sampling secondary voltage and secondary current signals; A controller, wherein the input end of the controller is connected to the output end of the sampling board, and the output end is connected to the input end of the inverter; The three-phase AC power is output to the load via the rectifier, the inverter and the transformer, and the controller controls the power supply device after receiving the secondary voltage and secondary current electrical signals collected by the sampling board; The secondary voltage and secondary current signals are obtained by the control method of the high-frequency power supply for dust removal.

Images